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2022-06-14: M.C. Escher's Birthday Challenge starts June 17th

The fourth challenge of the 2022 Series will be a 5-day challenge marking the 124th birthday of Maurits Cornelis Escher, one of the world?s most famous graphic artists. His art is admired by millions of people worldwide, as can be seen by the many websites on the internet. The challenge will be offered on the SR5-LLR application, beginning 17 June 13:00 UTC and ending 22 June 13:00 UTC.

To participate in the Challenge, please select only the Sierpinski/Riesel Base 5 Prime Search LLR (SR5) project in your PrimeGrid preferences section.

Comments? Concerns? Conundrums? Check out the forum thread for this challenge: http://www.primegrid.com/forum_thread.php?id=9941&nowrap=true#155914

Happy crunching!

2022-05-23: Geek Pride Day Challenge starts May 25

The third challenge of the 2022 Series will be a 5-day challenge celebrating geeks, freaks, nerds, dorks, dweebs, and "weird" people of all kinds! The challenge will be offered on the GFN-19 subproject, beginning 25 May 18:00 UTC and ending 30 May 18:00 UTC.

To participate in the Challenge, please select only the GFN-19 subproject in your PrimeGrid preferences section.

For more info and discussion, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9915&nowrap=true#155479

2022-05-22: GFN 19 Found!

On 15 May 2022, 17:29:48 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

4896418^524288+1

The prime is 3,507,424 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 54th overall.

The discovery was made by Tom Greer (tng) of the United States using a GeForce RTX 3060 in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 24GB RAM, running Microsoft Windows 10 Core x64 Edition. This GPU took about 1 hour, 1 minute to complete the probable prime (PRP) test using GeneferOCL2. Tom Greer is a member of Antarctic Crunchers.

The prime was verified on 16 May 2022, 19:12:23 UTC by Albert Pastuszka (User B@P) of Poland using a GeForce GTX 750 in an AMD Athlon(tm) II X3 445 Processor with 6GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 6 hours, 46 minutes to complete the probable prime (PRP) test using GeneferOCL2. Albert Pastuszka is a member of BOINC@Poland.

The PRP was confirmed prime by an AMD Ryzen 5 3600 6-Core Processor with 4GB RAM, running Linux Ubuntu. This computer took about 22 hours, 17 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2022-05-08: Another 321 Mega Prime!

On 24 March 2022, 17:27:33 UTC, PrimeGrid?s 321 Prime Search found the Mega Prime:

3*2^18924988-1

The prime is 5,696,990 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 18th overall.

The discovery was made by Frank Matillek (boss) of Germany using an Intel CPU with 1GB RAM, running Ubuntu Linux. This computer took about 1 day, 1 hour, 39 minutes to complete the primality test using LLR2. Frank Matillek is a member of the SETI.Germany team.

For more details, please see the official announcement.

2022-05-08: 321 Mega Prime!

On 8 January 2022, 20:46:05 UTC, PrimeGrid?s 321 Prime Search found the Mega Prime:

3*2^18196595-1

The prime is 5,477,722 digits long and has entered Chris Caldwell's ?The Largest Known Primes Database? ranked 20th overall.

The discovery was made by an anonymous user of Poland using an Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 edition. This computer took about 2 hours, 40 minutes to complete the primality test using LLR2.

For more details, please see the official announcement.

2022-03-17: World Water Day Challenge starts March 21st

The second challenge of the 2022 Series will be a 5-day challenge in celebration of World Water Day, the annual United Nations Observance, started in 1993, that celebrates water and raises awareness of the 2 billion people currently living without access to safe water. The challenge will be offered on the 321-LLR application, beginning 21 March 03:21 UTC and ending 26 March 03:21 UTC.

To participate in the Challenge, please select only the 321 Prime Search LLR (321) project in your PrimeGrid preferences section.

For more info and discussion, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9888&nowrap=true#154866

2022-01-13: Special caution regarding the upcoming Heptadecagenarian challenge

In a few days, PrimeGrid will be running its first challenge of the 2022 season.

In one important way, this challenge is different than any other challenge we've ever run before.

While the challenge is for both GFN-17-Low and GFN-17-MEGA, the main purpose of this challenge is to finish off the GFN-17-Low sub-project. This means that we will almost certainly run out of tasks for GFN-17-Low during the challenge. It's even possible GFN-17-Low will run out of tasks before the challenge even starts.

For this reason, it's important that participants also select GFN-17-MEGA, otherwise there is a significant risk that computers will run out of tasks during the challenge.

The challenge starts on January 17th, at 17:17:00 UTC, and will run for three days, ending on January 20th at 17:16:59.

The forum thread for the challenge is located here.

2021-12-16: SR5 Mega Prime Find!

On 7 December 2021, 14:48:06 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=273662 by finding the mega prime:

273662*5^3493296-1

The prime is 2,441,715 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 97th overall. 60 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Lukas Pl

2021-12-14: ESP Mega Prime!

On 25 November 2021, 03:19:26 UTC, PrimeGrid's Extended Sierpinski Problem found the Mega Prime:

202705*2^21320516+1

The prime is 6,418,121 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 13th overall. This find eliminates k=202705; 8 k's remain in the Extended Sierpinski Problem.

The discovery was made by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Xeon(R) E5-2695 v2 CPU @ 2.40GHz with 16GB RAM running Tiny Core Linux. This computer took about 10 hours, 59 minutes to complete the primality test using LLR2. Pavel is a member of the Ural Federal University team.

For more details, please see the official announcement.

2021-12-07: PRS Prime Find!

On 18 September 2021, 06:50:25 UTC, PrimeGrid?s Primorial Prime Search, through PRPNet found the mega prime:

3267113#-1

The prime is 1,418,398 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 1st for Primorial primes and 286th overall.

The discovery was made by James Winskill (Aeneas) of New Zealand using an Intel(R) Xeon(R) W-2125 CPU @ 4.00GHz with 64GB RAM running Windows 10. This computer took 20 hours 32 minutes to complete the prp test using pfgw64. James Winskill is a member of the PrimeSearchTeam.

The prp was verified on 26 September 2021, 01:56:46 UTC by an Intel i7-7700K @ 4.2 GHz with 16 GB RAM, running Gentoo/Linux. This computer took a little over 5 days 8 hours 38 minutes to verify primality of the prp using pfgw64.

For more details, please see the official announcement.

2021-12-04: Geminids Shower Challenge starts December 7th

The ninth and final challenge of the 2021 Series will be a 10-day challenge marking the yearly Geminids Meteor Shower. The challenge will be offered on the GFN-21, GFN-22, and GFN-DYFL subprojects, beginning 7 December 07:00 UTC and ending 17 December 07:00 UTC.

To participate in the Challenge, please select only the GFN-21 and/or GFN-22 and/or GFN-DYFL subprojects in your PrimeGrid preferences section.

For more info and discussion, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9804&nowrap=true#152440

2021-12-03: SR5 Mega Prime Find!

On 8 October 2021, 01:38:53 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=102818 by finding the mega prime:

102818*5^3440382-1

The prime is 2,404,729 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 96th overall. 61 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Wes Hewitt (emoga) of Canada using an AMD Ryzen 9 5950X 16-Core Processor with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 hour, 29 minutes to complete the primality test using LLR2. Wes Hewitt is a member of TeAm AnandTech team.

The prime was verified on 10 October 2021, 20:14 UTC, by an Intel(R) Core(TM) i7-9800X CPU @ 3.80GHz with 32GB of RAM, running CentOS. This computer took 20 hours and 39 minutes to complete the primality test using LLR2.

For more details, please see the official announcement.

2021-11-20: Euler's Number Challenge starts November 23rd

The eighth challenge of the 2021 Series will be a 3-day challenge in Thanksgiving? of the anniversary of the introduction of e, or Euler's Number! The challenge will be offered on the AP27 Search subproject, beginning 23 November 05:00 UTC and ending 26 November 05:00 UTC.

To participate in the Challenge, please select only the AP 27 (AP27) project in your PrimeGrid preferences section.

For more info and discussion, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9792&nowrap=true#152286

Best of luck!

2021-11-14: GFN-17-Low will is finishing

The GFN-17-LOW project has less than a million candidates to be tested, and thus will come to an end in the next few months.

Forum discussion thread: https://www.primegrid.com/forum_thread.php?id=9796

2021-11-14: GFN-17-Low is finishing

The GFN-17-LOW project has less than a million candidates to be tested, and thus will come to an end in the next few months.

Forum discussion thread: https://www.primegrid.com/forum_thread.php?id=9796

2021-11-06: WW (Wieferich Wall-Sun-Sun) is back online

The WW subproject is back online.

2021-11-05: WW (Wieferich Wall-Sun-Sun) temporarily offline

We've had to temporarily disable the WW project due to a problem identified in the work generator. The affected tasks have been cancelled and generation of new workunits has been suspended.

Tasks that are not affected will complete normally, and you can continue running them to completion.

This only affects the WW subproject. Feel free to switch to our other subprojects while WW is taking a "mental health day".

For more information and discussion, please see this thread: https://www.primegrid.com/forum_thread.php?id=9786

2021-10-18: Martin Gardner's Birthday Challenge starts October 21

The seventh challenge of the 2021 Series will be a 7-day challenge in celebration of the 107th (prime number!) birthday of beloved American science communicator, Martin Gardner. The challenge will be offered on the GCW-LLR application, beginning 21 October 00:00 UTC and ending 28 October 00:00 UTC.

To participate in the Challenge, please select only the Generalized Cullen/Woodall Prime Search LLR (GCW) project in your PrimeGrid preferences section.

For more info and discussion, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9767&nowrap=true#151803

Best of luck!

2021-09-23: 321 Mega Prime!

On 6 September 2021, 07:16:28 UTC, PrimeGrid's 321 Search found the Mega Prime:

3*2^17748034-1

The prime is 5,342,692 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 18th overall.

The discovery was made by Marc Wiseler (McDaWisel) of Ireland using an AMD Ryzen 9 5900X 12-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 hours, 45 minutes to complete the primality test using LLR2. Marc Wiseler is a member of the Storm team.

The prime was verified on 6 September 2021, 11:47 UTC, by an Intel(R) Core(TM) i7-9800X CPU @ 3.80GHz with 32GB of RAM, running CentOS. This computer took 2 hours and 41 minutes to complete the primality test using LLR2.

For more details, please see the official announcement.

2021-09-23: World Record Generalized Cullen Prime!

On 28 August 2021, 09:10:17 UTC, PrimeGrid?s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:

2525532*732525532+1

Generalized Cullen numbers are of the form: n*bn+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see ?Cullen prime? in The Prime Glossary.

The prime is 4,705,888 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 24th overall.

Base 73 was one of 10 primeless Generalized Cullen bases for b ?121 that PrimeGrid is searching. The remaining bases are 13, 29, 47, 49, 55, 69, 101, 109 & 121.

The discovery was made by Tom Greer (tng) of the United States using an Intel(R) Core(TM) i9-10920X CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 10 hours, 40 minutes to complete the primality test using LLR2. Tom is a member of the Antarctic Crunchers team.

The prime was verified on 28 August 2021, 18:01 UTC, by an Intel(R) Core(TM) i7-9800X CPU @ 3.80GHz with 32GB of RAM, running CentOS. This computer took 3 hours and 39 minutes to complete the primality test using LLR2.

For more details, please see the official announcement.

2021-08-10: Once In A Blue Moon Challenge starts August 12

The sixth challenge of the 2021 Series will be a 10-day challenge leading up to a relatively rare astronomical event called a blue moon. The challenge will be offered on the PSP-LLR application, beginning 12 August 20:00 UTC and ending 22 August 20:00 UTC.

To participate in the Challenge, please select only the Prime Sierpinski Problem LLR (PSP) project in your PrimeGrid preferences section.

For more info, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9720&nowrap=true#151032

Best of luck!

2021-07-15: World Emoji Day Challenge starts July 17th

The fifth challenge of the 2021 Series will be a 3-day challenge in celebration of what is arguably the internet's most momentous and culturally significant holiday: World Emoji Day. The challenge will be offered on the GFN-17-Low subproject, beginning 17 July 22:00 UTC and ending 20 July 22:00 UTC.

To participate in the Challenge, please select only the GFN-17-Low subproject in your PrimeGrid preferences section.

For more info, check out the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9706&nowrap=true#150796

Best of luck!

2021-07-01: DIV Mega Prime! (Belated Posting)

On 1 March 2021, 02:47:51 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

25*2^8788628+1

The prime is 2,645,643 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 75th overall.

The discovery was made by Tom Greer (tng) of the United States using an Authentic AMD Ryzen 9 5950X CPU @ 4.90GHz with 32GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours and 46 minutes to complete the primality test using LLR2. Tom Greer is a member of the Antarctic Crunchers team.



For more details, please see the official announcement.

2021-06-09: PrimeGrid's 16th Birthday Challenge starts June 12

The fourth challenge of the 2021 Series will be a 5-day challenge celebrating the 16th anniversary of the launch of PrimeGrid on BOINC. The challenge will be offered on the ESP-LLR application, beginning 12 June 13:00 UTC and ending 17 June 13:00 UTC.

To participate in the Challenge, please select only the Extended Sierpinski Problem LLR (ESP) project in your PrimeGrid preferences section.

For more information, check out the forum thread for this challenge:
https://www.primegrid.com/forum_thread.php?id=9684&nowrap=true#150570

Best of luck!

2021-04-08: Yuri's Night Challenge starts April 11th

The third challenge of the 2021 Series will be a 3-day challenge celebrating the 60th anniversary of Yuri Gagarin's history-making venture into outer space. The challenge will be offered on the WW application, beginning 11 April 18:00 UTC and ending 14 April 18:00 UTC.

This is a relatively new subproject here at PrimeGrid, and there are currently no known Wall?Sun?Sun primes! You could be the first to find one!

To participate in the Challenge, please select only the Wieferich and Wall-Sun-Sun Prime Search (WW) project in your PrimeGrid preferences section.

Questions? Queries? Quips? Discuss on the forum thread for this challenge. Best of luck!

2021-03-14: An Ending and a Beginning

This is the End...

Yesterday, the last task in our Fermat Divisor Search was sent out for processing. While there will likely be a few resends available over the next week or two, if you have PPS-DIV selected as your only project, we recommend choosing something else.

This project was very successful, having found two Fermat divisors! Congratulations everyone, and thank you for participating.

Discussion about the Fermat divisor search can be found here: https://www.primegrid.com/forum_forum.php?id=121

...And Also the Beginning

In less than an hour, at 12:00 UTC on Pi Day, our Sier"pi"nski's Birthday Challenge will be starting. This is a 10 day challenge on our Seventeen or Bust (SoB) project.

Details and discussion about the challenge can be found here: https://www.primegrid.com/forum_thread.php?id=9614

2021-03-03: DIV Mega Prime!

On 17 February 2021, 14:27:08 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

17*2^8636199+1

The prime is 2,599,757 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 76th overall.

The discovery was made by Tom Greer (tng) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 5 hours to complete the primality test using LLR2. Tom Greer is a member of the Antarctic Crunchers team.

For more details, please see the official announcement.

2021-03-03: TRP Mega Prime!

On 7 February 2021, 18:01:10 UTC, PrimeGrid?s The Riesel Problem project eliminated k=9221 by finding the mega prime:

9221*2^11392194-1

The prime is 3,429,397 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 44th overall. This is PrimeGrid's 17th elimination. 47 k's now remain.

The discovery was made by Barry Schnur (BarryAZ) of the United States using an AMD Ryzen 5 2600 Six-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 days, 29 minutes to complete the primality test using LLR2. Barry Schnur is a member of the BOINC Synergy team.

For more details, please see the official announcement.

2021-03-03: New 27 Mega Prime!

On 01 February 2021 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet found the mega prime:

27*2^8342438-1

The prime is 2,511,326 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 77th overall.

The discovery was made by Andrew M. Farrow (Nortech) of Australia using an Intel(R) Core(TM) i3-4170 CPU @ 3.70GHz with 4GB RAM, running Linux. This computer took just over 3 hours 19 minutes to complete the primality test using LLR.

The prime was verified on 01 February 2021, 15:42:26 UTC, by an Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz with 8 GB RAM, running Linux Manjaro. This computer took just under 2 hours 19 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2021-02-01: Another DIV Mega Prime!

On 27 January 2021, 17:13:11 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

25*2^8456828+1

The prime is 2,545,761 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 74th overall.

The discovery was made by Wolfgang Schwieger (DeleteNull) of Germany using an AMD Ryzen 7 3700X 8-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 hour, 20 minutes to complete the primality test using LLR2. Wolfgang Schwieger is a member of the SETI.Germany team.

For more details, please see the official announcement.

2021-02-01: And Another DIV Mega Prime!

On 23 January 2021, 03:37:22 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

39*2^8413422+1

The prime is 2,532,694 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 74th overall.

The discovery was made by Philipp Bliedung (pabliedung) using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu Ubuntu 18.04.3 LTS [4.15.0-72-generic|libc 2.27 (Ubuntu GLIBC 2.27-3ubuntu1.2)]. This computer took about 2 hours, 5 minutes to complete the primality test using LLR2. Philipp Bliedung is a member of the USA team.

For more details, please see the official announcement.

2021-02-01: 321 Mega Prime!

On 20 January 2021, 11:58:27 UTC, PrimeGrid's 321 Search found the Mega Prime:

3*2^16819291-1

The prime is 5,063,112 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 21st overall.

The discovery was made by Rudi Tapper (ruditapper) of the United Kingdom using an AMD Ryzen Threadripper 3990X 64-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 5 hours, 40 minutes to complete the primality test using LLR2. Rudi Tapper is a member of the Antarctic Crunchers team.

For more details, please see the official announcement.

2021-02-01: Another DIV Mega Prime!

On 19 January 2021, 15:48:46 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

31*2^8348000+1

The prime is 2,513,000 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 73rd overall.

The discovery was made by Igor Karpenko (A1ex01) of Ukraine using an Intel(R) Core(TM) i5-8400 CPU @ 2.80GHz with 4GB RAM, running Linux. This computer took about 2 hours, 52 minutes to complete the primality test using LLR. Igor Karpenko is a member of the Ukraine team.

For more details, please see the official announcement.

2021-02-01: Fermat Divisor Found!

On 14 January 2021, 18:15:44 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

27*2^7963247+1 Divides F(7963245)

The prime is 2,397,178 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 74th overall. This is ranked 2nd for prime Fermat divisors, and it is also ranked 2nd for ?weighted? prime Fermat divisors.

The discovery was made by Tom Greer (tng) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 3 hours, 58 minutes to complete the primality test using LLR2. Tom Greer is a member of the Antarctic Crunchers team.

For more details, please see the official announcement.

2021-02-01: Another DIV Mega Prime!

On 14 January 2021, 14:16:38 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

39*2^7946769+1

The prime is 2,392,218 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 74th overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Xeon(R) CPU E5-2697 v2 @ 2.70GHz with 120GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 4 hours, 15 minutes to complete the primality test using LLR2. Scott Brown is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2021-02-01: DIV Mega Prime!

On 14 January 2021, 04:06:53 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

29*2^7899985+1

The prime is 2,378,134 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 76th overall.

The discovery was made by Tom Greer (tng) of the United States using an Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 10 Core x64 Edition. This computer took about 2 hours, 1 minute to complete the primality test using LLR2. Tom Greer is a member of the Antarctic Crunchers team.

For more details, please see the official announcement.

2021-01-11: Good Riddance 2020! Challenge starts January 14th

The first challenge of the 2021 Series will be a 5-day challenge celebrating the end of the abomination which was the year 2020. The challenge will be offered on the PPS-DIV (LLR) application, beginning 14 January 00:00 UTC and ending 18 January 23:59 UTC.

To participate in the Challenge, please select only the Fermat Divisor Search LLR (PPS-DIV) project in your PrimeGrid preferences section.

Comments? Concerns? Discuss on the forum post for this challenge. Best of luck!

2021-01-10: Another DIV Mega Prime!

On 13 December 2020, 16:07:34 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

45*2^7661004+1

The prime is 2,306,194 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 77th overall.

The discovery was made by Tim Terry (TimT) of the United States using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 32GB RAM, running Linux Fedora. This computer took about 1 hour, 10 minutes to complete the primality test using LLR2. Tim Terry is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2021-01-10: DIV Mega Prime!

On 6 December 2020, 02:07:48 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

15*2^7619838+1

The prime is 2,293,801 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 78th overall.

The discovery was made by an anonymous user of China using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 hours to complete the primality test using LLR2.

For more details, please see the official announcement.

2020-12-27: Change in Prime Reporting Procedure

With the release of LLR2, we are seeing a dramatic increase in the number of primes found by users that don't give permission to report them. To decrease the number of primes stuck waiting for permission to report that we never receive, we will still wait nineteen days for the first prime found by a user, but only seven days for subsequent primes before moving to the double checker or reporting as anonymous.

If you have primes reported to T5K through PrimeGrid already or have given permission to report and provided your name, this doesn't affect you. Otherwise, I strongly encourage you to change your PrimeGrid preferences to give permission.

2020-12-18: Great Conjunction Challenge starts December 21

The ninth and final challenge of the 2020 Series will be a 10-day challenge marking the extraordinarily rare astronomical event known as the Great Conjunction. The challenge will be offered on the GFN-18, GFN-19, and GFN-20 subprojects, beginning 21 December 13:22 UTC and ending 31 December 13:22 UTC.

To participate in the Challenge, please select only the GFN-18 and/or GFN-19 and/or GFN-20 subprojects in your PrimeGrid preferences section.

Addendums? Annotations? Apprehensions? Discuss in the forum thread for this challenge. Best of luck!

2020-12-08: New 121 Mega Prime!

On 18 Nov 2020, 05:40:34 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet found the mega prime:

121*2^9584444+1

The prime is 2,885,208 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 60th overall.

The discovery was made by James Winskill (Aeneas) of New Zealand using an Intel Xeon(R) E5-2637 v3 CPU @ 3.50GHz with 64GB RAM, running Microsoft Windows Server 2012 R2. This computer took just under 13 hours 49 minutes to complete the primality test using LLR. James Winskill is a member of the PrimeSearchTeam.

The prime was verified on 18 Nov 2020, 16:42:00 UTC, by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16 GB RAM, running Linux Gentoo. This computer took a little over 1 hour 42 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-12-04: Changes to GFN Apps

I just installed the new Windows and Linux (but not Mac) CPU versions for the following GFN projects:

GFN-16 Yes, you can run GFN16 on CPUs again!
GFN-17-LOW
GFN-17-MEGA Yes, you can run GFN-17-MEGA on CPUs again!
GFN-18
GFN-19
GFN-20

Genefer 3.3.5 provides substantial speed boosts for CPU on those projects.

This applies only to the CPU apps. GPU apps are not affected.

GFN-21 has not been updated because it's still capable of running the FP64 transforms, which are the fastest.

I have removed the CPU GFN-22 app. It was a mistake.

Mac versions of the new app will be made available when testing is completed, but this has been delayed by a lack of Mac testers.

If you want to help out testing the Mac version, head over to the 3.3.5 testing thread.

Discussion about the new release can be found in the Genefer 3.3.5 release thread.

2020-11-28: New Subproject!

For the first time in a while, we have a new subproject: the Wieferich and Wall-Sun-Sun Prime Search!

To participate, edit your project preferences. The app is available for GPU and CPU.

Note: there may be severe screen lag on the GPU Mac version. We are aware and a fix will be out soon.

See this forum thread for more information about the search.

2020-11-25: TRP Mega Prime!

On 16 November 2020, 23:17:01 UTC, PrimeGrid?s The Riesel Problem project eliminated k=146561 by finding the mega prime:

146561*2^11280802-1

The prime is 3,395,865 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 42nd overall. This is PrimeGrid's 16th elimination. 48 k's now remain.

The discovery was made by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Xeon(TM) E5-2680 v4 CPU @ 2.40GHz with 4GB RAM, running Linux. This computer took about 3 hours, 18 minutes to complete the primality test using LLR2. Pavel Atnashev is a member of the Ural Federal University team.

For more details, please see the official announcement.

2020-11-18: DIV Mega Prime!

On 12 November 2020, 06:43:56 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

45*2^7513661+1

The prime is 2,261,839 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 73rd overall.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 32GB RAM, running Linux 4.4.0-21-generic. This computer took about 2 hours, 6 minutes to complete the primality test using LLR. Hiroyuki Okazaki is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2020-11-16: Magellan 500th Anniversary Challenge starts 18 November

The eighth challenge of the 2020 Series will be a 10-day challenge commemorating the (approximate) 500th Anniversary of the extraordinary expedition of Portuguese explorer Ferdinand Magellan. The challenge will be offered on the CUL-LLR and WOO-LLR subprojects, beginning 18 November 18:00 UTC and ending 28 November 18:00 UTC.

To participate in the Challenge, please select only the Cullen Prime Search LLR (CUL) and/or Woodall Prime Search LLR (WOO) projects in your PrimeGrid preferences section. Work units which are downloaded and completed during the challenge will count towards your challenge score.

Note: This will be our second challenge using LLR2, which eliminates the need for a full doublecheck task on each workunit, but replaces it with a short verification task. Expect to receive a few tasks about 1% of normal length.

Comments? Concerns? Conundrums? Confusions? Think we'll break the decade-long drought of Cullen primes? Tell us in the forum thread for this challenge. Best of luck!

2020-11-04: 321 Sieve is over

The 321 Sieve project has come to an end, and no more 321 Sieve tasks will be sent out.

If you currently have only 321-Sieve tasks selected, I suggest switching to the PPS-Sieve project. It's a similar task, albeit longer in duration.

2020-10-31: DIV Mega Prime!

On 27 October 2020, 22:38:04 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

29*2^7374577+1

The prime is 2,219,971 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 73rd overall.

The discovery was made by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHz with 4GB RAM, running Microsoft Windows 7 Professional x64 Edition. This computer took about 1 hour, 49 minutes to complete the primality test using LLR2. Pavel Atnashev is a member of the Ural Federal University team.

For more details, please see the official announcement.

2020-10-31: 321 Mega Prime!

On 25 October 2020, 11:30:07 UTC, PrimeGrid's 321 Search found the Mega Prime:

3*2^16408818+1

The prime is 4,939,547 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 21st overall.

The discovery was made by Dr. James Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4770S CPU @ 3.10GHz with 8GB RAM, running Microsoft Windows 10 Enterprise x64 Edition. This computer took about 6 hours, 6 minutes to complete the primality test using LLR2. Dr. James Scott Brown is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2020-10-27: How About One More DIV Mega Prime!

On 25 October 2020, 00:52:15 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

15*2^7300254+1

The prime is 2,197,597 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 75th overall.

The discovery was made by Robert Gelhar (Gelly) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 3 hours, 24 minutes to complete the primality test using LLR. Robert Gelhar is a member of the Antarctic Crunchers team.


For more details, please see the official announcement.

2020-10-27: And Another DIV Mega Prime!

On 24 October 2020, 22:53:39 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

19*2^6833086+1

The prime is 2,056,966 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 94th overall.

The discovery was made by Jiri Jaros (Venec) of the Czech Republic using an Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz with 8GB RAM, running Linux Ubuntu. This computer took about 7 hours, 27 minutes to complete the primality test using LLR. Jiri Jaros is a member of the Czech National Team team.


For more details, please see the official announcement.

2020-10-27: Another DIV Mega Prime!

On 20 October 2020, 19:06:13 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

39*2^6684941+1

The prime is 2,012,370 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 97th overall.

The discovery was made by Mike Th

2020-10-27: New DIV Mega Prime!

On 20 October 2020, 13:22:13 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

39*2^6648997+1

The prime is 2,001,550 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 99th overall.

The discovery was made by Tom Greer (tng) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 2 hours, 38 minutes to complete the primality test using LLR. Tom Greer is a member of the Antarctic Crunchers team.


For more details, please see the official announcement.

2020-10-19: ?variste Galois Challenge starts TOMORROW, October 20th

The seventh challenge of the 2020 Series will be a 5-day challenge celebrating the 209th birthday of

2020-09-21: 321 Sieve is being SUSPENDED

On October 21st, we will be suspending our 321 Sieve project.

Details and discussion can be found here.

2020-09-05: Warning about the end of the challenge

Despite our best efforts, we're not sure the server is going to make it to the end of the challenge. We're not asking people to stop crunching, but we are advising anyone who may be "bunkering" tasks for a competitive push at the end that the server may be unavailable. Please make sure all your tasks are counted by getting them back to the server as soon as possible!

THe challenge discussion thread can be found here: https://www.primegrid.com/forum_thread.php?id=9271

2020-08-31: International Bacon Day Challenge starts September 3rd

In honor of the day arbitrarily chosen by three graduate students at the University of Colorado Boulder to celebrate this notorious breakfast meat, PrimeGrid will be running a 3-day PPSE-LLR challenge from 3 September 00:00 UTC to 6 September 00:00 UTC.

Work units from the Proth Prime Search Extended (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

The work units are big enough to earn you a spot on the Top 5000 list if you score a prime, but small enough that your chances are as high as 1 in 30,000 per task! That might not sound like a lot, but an average 4-core CPU can churn out nearly 300 per day. Best of luck!

Inquiries? Inspirations? Introspections? Do you have a finite Bacon Number? Tell us in the forum thread for this challenge: https://www.primegrid.com/forum_thread.php?id=9271

2020-08-20: SR5 Mega Prime!

On 13 August 2020, 17:09:10 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=109838 by finding the mega prime:

109838*5^3168862-1

The prime is 2,214,945 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 72ns overall and is the largest known base 5 prime. 62 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Erik Veit (zombie67 [MM]) of the United States AMD Ryzen Threadripper 3970X 32-Core Processor with 63GB RAM, running Linux Mint. This computer took about 6 hours, 14 minutes to complete the primality test using LLR. Erik Veit is a member of the SETI.USA team.

The prime was verified on 13 August 2020, 22:53:05 UTC by Frederik Schi

2020-07-21: Katherine Johnson Memorial Challenge starts July 24th

In honor of the life of Katherine Johnson, PrimeGrid will be running a 7-day TRP-LLR challenge from 24 July 20:00 UTC to 31 July 20:00 UTC. Will we end this subproject's 3-year prime drought?

Also make sure to read Hidden Figures, a book about Katherine Johnson and some of her contemporaries, for the book club meeting!

Doubts? Disputes? Dubieties? Discuss in the forum thread for the challenge: https://www.primegrid.com/forum_thread.php?id=9217

2020-06-21: GFN-524288 Find!

On 29 May 2020, 07:52:25 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

3638450^524288+1

The prime is 3,439,810 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 35th overall.

The discovery was made by Wolfgang Schwieger (DeleteNull)of Germany using a GeForce RTX 2070 in an AMD Ryzen 7 3700X 8-Core Processor with 16GB RAM, running Linux openSUSE . This GPU took about 31 minutes to complete the probable prime (PRP) test using GeneferOCL5. Wolfgang Schwieger is a member of the SETI.Germany Team.

The PRP was verified on 29 May 2020, 08:23:51 UTC by Greg Miller (Olgar) of the United States using a gfx1010 in an AMD FX-8370 Eight-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 hour, 3 minutes to complete the probable prime (PRP) test using GeneferOCL5. Greg Miller is a member of the USA Team.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian . This computer took about 1 day, 19 hours, 22 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-05-10: SR5 Mega Prime!

On 1 May 2020, 04:01:08 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=118568 by finding the mega prime:

118568*5^3112069+1

The prime is 2,175,248 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 70th overall and is the largest known base 5 prime. 30 k?s now remain in the Sierpinski Base 5 problem.

The discovery was made by Honza Cholt (Honza) of the Czech Republic using an Intel(R) Core(TM) i7-9700K CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 49 minutes to complete the primality test using LLR. Honza Cholt is a member of Czech National Team.

The prime was verified on 2 May 2020, 09:00:41 UTC by Tom Murphy VII (brighterorange) of the United States using an AMD Ryzen Threadripper 2990WX 32-Core Processor with 128GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 day, 1 hour, 55 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-03-31: And Another SR5 Mega Prime!

On 16 March 2020, 08:21:46, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=207494 by finding the mega prime:

207494*5^3017502-1

The prime is 2,109,149 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 75th overall and is the largest known base 5 prime. 63 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Todd Pickering (EXT64) of Germany using an the United States using an AMD EPYC 7601 32-Core Processor with 126GB RAM, running Linux Ubuntu. This computer took about 1 day, 17 hours, 59 minutes to complete the primality test using LLR. Todd Pickering is a member of the [H]ard|OCP team.

The prime was verified internally using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 32GB RAM, running Linux Debian.

For more details, please see the official announcement.

2020-03-31: Another SR5 Mega Prime!

On 12 March 2020, 19:16:51 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=238694 by finding the mega prime:

238694*5^2979422-1

The prime is 2,082,532 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 76th overall and is the largest known base 5 prime. 64 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Chris Howell (Khali) of the United States using an Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 5 hours, 56 minutes to complete the primality test using LLR. Chris Howell is a member of the Crunching@EVGA team.

The prime was verified on 13 March 2020, 21:25:52 UTC by Yuki Yoshigoe (SAKAGE@AMD@jisaku) of Japan using an AMD Ryzen Threadripper 3970X 32-Core Processor with 128GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 day, 5 hours, 24 minutes to complete the primality test using LLR. Yuki Yoshigoe is a member of the Team 2ch team.

For more details, please see the official announcement.

2020-03-31: SR5 Mega Prime!

On 9 March 2020, 21:32:46, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=146264 by finding the mega prime:

146264*5^2953282-1

The prime is 2,064,261 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 74th overall and is the largest known base 5 prime. 65 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Wolfgang Schwieger (DeleteNull) of Germany using an Intel(R) Core(TM) i5-8600K CPU @ 3.60GHz with 8GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 6 hours, 25 minutes to complete the primality test using LLR. Wolfgang Schwieger is a member of the SETI.Germany team.

The prime was verified internally using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 32GB RAM, running Linux Debian.

For more details, please see the official announcement.

2020-03-11: SR5 Mega Prime!

On 5 March 2020, 14:40:22 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=35816 by finding the mega prime:

35816*5^2945294-1

The prime is 2,058,677 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 73rd overall and is the largest known base 5 prime. 66 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Xeon(R) E5-2660 v2 CPU @ 2.20GHz with 8GB RAM running Linux. This computer took about 3 hours 56 minutes to complete the primality test using LLR. Pavel Atnashev is a member of the Ural Federal University team.

The prime was verified on 6 March 2020, 21:41:36 UTC by John Hall (JH30895) of the United States using an Intel(R) Xeon(R) W-3245 CPU @ 3.20GHz with 385GB RAM, running Darwin 19.3.0. This computer took about 1 day, 7 hours 33 minutes to complete the primality test using LLR. John Hall is a member of the Antarctic Crunchers team.

For more details, please see the official announcement.

2020-03-08: Year of the Rat Challenge

Happy (very late) Chinese New Year! Even though the timing was awkward this year, this 5-day SR5 challenge from 12 March 06:00 UTC to 17 March 06:00 UTC will celebrate the Year of the Rat!

We've already eliminated one K-value from the Base-5 Riesel Problem this month -- will the luck of the Rat continue?

Questions? Comments? Concerns? Existential quandaries? Discuss in the forum post for the challenge: https://www.primegrid.com/forum_thread.php?id=9063

2020-02-27: Another GFN-262144 Find!!

On 16 February 2020, 01:13:42 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

9812766^262144+1

The prime is 1,832,857 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th for Generalized Fermat primes and 87th overall.

The discovery was made by Tom Greer (tng*) of the United States using an NVidia GeForce RTX 2070 in an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Core x64 Edition. This GPU took about 17 minutes to complete the probable prime (PRP) test using GeneferOCL2. Tom Greer is a member of the Sicituradastra. team.

The prime was verified on 16 February 2020, 01:39:49 UTC by Viktor Svantner (Viktor Svantner) of the Czech Republic using a GeForce GTX 1080 Ti in an AMD Ryzen Threadripper 2990WX 32-Core Processor with 128GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 22 minutes to complete the probable prime (PRP) test using GeneferOCL2. Viktor Svantner is a member of the Czech National Team team.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian. This computer took about 6 hours, 6 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-02-27: GFN-262144 Find!

On 12 February 2020, 14:26:58 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

9750938^262144+1

The prime is 1,832,137 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th for Generalized Fermat primes and 86th overall.

The discovery was made by Alen Kecic (Freezing) of Germany using an NVidia GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This GPU took about 22 minutes to complete the probable prime (PRP) test using GeneferOCL2. Alen Kecic is a member of the SETI.Germany team.

The prime was verified on 12 February 2020, 14:32:50 UTC by Tom Greer (tng*) of the United States using an NVidia GeForce RTX 2080 in an Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 13 minutes to complete the probable prime (PRP) test using GeneferOCL2. Tom Greer is a member of the Sicituradastra. team.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian. This computer took about 13 hours, 22 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-02-01: GFN-16 CPU tasks no longer available

We have exceeded the 'b' limit of the CPU version of the Genefer software on the GFN-16 project. No more GFN-16 CPU tasks will be sent.

GFN-16 GPU tasks will continue to be available.

Genefer CPU tasks continue to be available for GFN-17-Low, GFN-18, GFN-19, GFN-20, GFN-21, and GFN-22.

2020-01-25: World Record Fermat Divisor Found!

On 22 January 2020, 15:00:58 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:

13*2^5523860+1 Divides F(5523858)

The prime is 1,662,849 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 115th overall. This is a world record for prime Fermat divisors, and it is also ranked 4th for ?weighted? prime Fermat divisors.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Core x64 Edition. This computer took about 39 minutes to complete the primality test using multithreaded LLR. Scott is a member of the Aggie The Pew team.

The prime was verified on 22 January 2020, 15:11:39 UTC by Stefan Larsson (288larsson) of Sweden using an Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz with 8GB RAM, running Microsoft Windows 10 Core x64 Edition. This computer took about 46 minutes to complete the primality test using multithreaded LLR. Stefan is a member of the Sicituradastra. team.

For more details, please see the official announcement.

2020-01-22: Another GFN-262144 Find!!

On 21 January 2020, 00:49:54 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

9450844^262144+1

The prime is 1,828,578 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th for Generalized Fermat primes and 85th overall.

The discovery was made by Jacob Eikelenboom (Eikelenboom) of The Netherlands using an NVIDIA GeForce RTX 2060 in an Intel(R) Core(TM) i7-9700F CPU @ 3.00GHz with 16GB RAM, running Microsoft Windows 10 Core x64 Edition. This GPU took about 18 minutes to complete the probable prime (PRP) test using GeneferOCL2.

The prime was verified on 21 January 2020, 02:35:41 UTC by Igor Keller (IKI) of France using an NVIDIA GeForce GTX 1080 in an Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 8.1 Professional with Media Center x64 Edition. This computer took about 26 minutes to complete the probable prime (PRP) test using GeneferOCL2. Igor Keller is a member of the Gridcoin team.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian. This computer took about 17 hours, 52 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2020-01-20: International Day of Education Challenge

To celebrate UNESCO's International Day of Education, PrimeGrid is having a 1-day challenge on January 24th 2020, 00:00:00 UTC to 23:59:59 UTC.

Tasks from the 321-Sieve project which are downloaded and completed during the challenge will count towards your challenge score.

For more information and discussion, please see the official challenge thread: https://www.primegrid.com/forum_thread.php?id=8971

Best of luck!

2020-01-13: GFN-524288 Mega Prime!

On 24 December 2019, 08:20:15 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

3214654^524288+1

The prime is 3,411,613 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 30th overall.

The discovery was made by Alen Kecic (Freezing)of Germany using a GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This GPU took about 51 minutes to complete the probable prime (PRP) test using GeneferOCL5. Alen is a member of the SETI.Germany Team.

The PRP was verified on 24 December 2019, 10:12:18 UTC by John Holmes (John J. Holmes) of the United States using a GeForce GTX 970 in an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 hours, 4 minutes to complete the probable prime (PRP) test using GeneferOCL3.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 day, 1 hour, 45 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2020-01-13: ESP Mega Prime!

On 24 December 2019, 01:28:13 UTC, PrimeGrid's Extended Sierpinski Problem found the Mega Prime:

99739*2^14019102+1

The prime is 4,220,176 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 20th overall. This find eliminates k=99739; 9 k's remain in the Extended Sierpinski Problem.

The discovery was made by Brian D. Niegocki (Penguin) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 14 hours, 14 minutes to complete the primality test using LLR. Brian is a member of the Antarctic Crunchers team.

The prime was verified on 24 December 2019, 04:37:31 UTC by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Xeon(R) E5-2680 v2 @ 2.80GHz with 8GB RAM, running Linux. This computer took about 4 hours, 6 minutes to complete the primality test using LLR. Pavel is a member of the Ural Federal University team.

For more details, please see the official announcement.

2019-12-24: And Another GFN-262144 Find!!

On 5 December 2019, 08:39:29 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

9125820^262144+1

The prime is 1,824,594 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th for Generalized Fermat primes and 82nd overall.

The discovery was made by Yoshimitsu Kato (yoshi) of Japan using a GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10. This GPU took about 22 minutes to complete the probable prime (PRP) test using Genefer OCL2. Yoshimitsu Kato is a member of Team JPN.

The prime was verified on 5 December 2019, 08:41:59 UTC by Igor Keller (IKI) of France using a GeForce GTX 1080 in an Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 8.1. This GPU took about 26 minutes to complete the probable prime (PRP) test using Genefer OCL2. Igor Keller is a member of the Gridcoin team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 16 hours, 30 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-12-24: GFN-262144 Find!

On 6 November 2019, 11:59:08 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:

8883864^262144+1

The prime is 1,821,535 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th for Generalized Fermat primes and 80th overall.

The discovery was made by Rod Skinner (rjs5) of the United States using a GeForce RTX 2080 Ti in an Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz with 63GB RAM, running Linux Fedora. This GPU took about 8 minutes to complete the probable prime (PRP) test using Genefer OCL2. Rod Skinner is a member of Intel Corporation team.

The prime was verified on 6 November 2019, 14:33:32 UTC by Tom Greer (tng*) of the United States using a GeForce RTX 2070 SUPER in an Intel(R) Core(TM) i9-9900X CPU @ 3.50GHz with 32GB RAM, running Microsoft Windows 10. This GPU took about 13 minutes to complete the probable prime (PRP) test using Genefer OCL2. Tom Greer is a member of the Sicituradastra. team.

The PRP was confirmed prime by an Intel(R) Xeon(R) E3-1240 v6 CPU @ 3.70GHz with 32 GB RAM, running Debian Linux. This computer took about 17 hours 30 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2019-12-08: Aussie Aussie Aussie! Oi! Oi! Oi! Summer Solstice Challenge

The longest day of the year (in the southern hemisphere!) is drawing near, and to mark this turning point in the year, PrimeGrid is offering a 10-day challenge on the GFN-21, GFN-22, and GFN-DYFL subprojects. Will you be the first to discover a prime in one of these so-far unlucky categories?

The challenge will run from December 12th 04:19:00 UTC until December 22nd 04:19:00 UTC.

For more information, questions and general banter and merry making please join us on the forums at https://www.primegrid.com/forum_thread.php?id=8916.

2019-12-04: Position Open: Challenge Coordinator

PrimeGrid is looking for someone to coordinate our BOINC challenges.

The challenge coordinator sets the schedule, creates the theme for each challenge, and communicates with the PrimeGrid community.

Reply to me via PM or respond here if you're interested or have questions.

2019-11-01: Transit of Mercury Across the Sun Challenge

Please join PrimeGrid as we run a 10 day challenge to celebrate this year's transit of Mercury across the sun. This rare astronomical event won't occur again until 2032.

This challenge runs from November 1st 18:04 UTC through November 11th 18:04 UTC on our PSP Prime Search (LLR) Project.

There's 7 k's being tested by our PSP project. Will we be able to find a prime for one of the remaining k's during the challenge? The last PSP prime was found in 2017. (Two additional k's are in both the PSP and SoB projects and are being tested as part of SoB.)

For more information and discussion, please head over to the official challenge thread: https://www.primegrid.com/forum_thread.php?id=8864

Good luck!

2019-10-22: 50 years First ARPANET Connection Challenge

Please join PrimeGrid as we run a 5 day challenge to celebrate 50 years from when the first ARPANET data message was sent between two networked computers. Arpanet was renamed the Internet in 1984, when it linked 1,000 hosts at university and corporate labs.

This challenge runs from October 24th 00:00 UTC through October 29th 00:00 UTC on our 321 Prime Search (LLR) Project.

Last month we found the first known AP27 during the Oktoberfest challenge. Will history repeat itself with the discovery of the first 321 prime in more than 4 years?

For more information and discussion, please head over to the official challenge thread: https://www.primegrid.com/forum_thread.php?id=8855

Good luck!

2019-09-30: First Ever AP27 Discovered!

The search is over!

After a three year effort, the first ever AP27 (Arithmetic Progression of 27 primes) has been found:

224584605939537911+81292139*23#*n for n=0..26

The AP27 was found by Rob Gahan (Robish) of Ireland. The discovery was made on an NVIDIA GeForce GTX 1660 Ti GPU on an Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz running Microsoft Windows 10 Professional x64 Edition. It took about 22 minutes and 34 seconds to process the task. Rob is a member of the Storm team.

Congratulations to everyone who participated in the AP27 search! It has been a very challenging and rewarding project.

For more information, please see the official announcement or our AP27 forums.

2019-09-24: GFN-524288 Mega Prime!

On 18 September 2019, 11:52:32 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2985036^524288+1

The prime is 3,394,739 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 28th overall.

The discovery was made by Peter Harvey (eXaPower) the United States using an NVIDIA GeForce GTX 1070 in an Intel(R) Core(TM) i5-4440S CPU @ 2.80GHz CPU with 8GB RAM, running Windows 8.1. This GPU took about 1 hour 49 minutes to probable prime (PRP) test with GeneferOCL3.

The PRP was verified on 19 September 2019, 22:56:55 UTC by Alexander Falk (Alexander Falk) using an NVIDIA GeForce GTX 970 in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Windows 10. This GPU took about 3 hours 17 minutes to probable prime (PRP) test with GeneferOCL5. Alexander is a member of The Knights Who Say Ni! Team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Windows 10 Professional. This computer took about 23 hours 48 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-09-24: GFN-262144 Find!

On 9 September 2019, 18:15:29 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

8521794^262144+1

The prime is 1,816,798 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 13th for Generalized Fermat primes and 76th overall.

The discovery was made by Ken Ito (jpldcon4) of Japan using an NVIDIA GeForce GTX 980 Ti in an Intel(R) Xeon(R) CPU E5-2687W v3 @ 3.10GHz with 64GB RAM, running Microsoft Windows Server 2016. This GPU took about 27 minutes to probable prime (PRP) test with GeneferOCL2. Ken is a member of Team 2ch.

The prime was verified on 10 September 2019, 02:21:44 UTC by Brent Schneider (KWSN-SpongeBob SquarePants) of Nepal using an NVIDIA GeForce GTX 1080 in an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Enterprise. This GPU took about 28 minutes to probable prime (PRP) test with GeneferOCL2. Brent is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Xeon(R) E3-1240 v6 CPU @ 3.70GHz with 32 GB RAM, running Debian Linux. This computer took about 17 hours 30 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2019-09-18: Oktoberfest Challenge!

From September 21st, 2019 Primegrid will be running an AP27 Challenge to celebrate Oktoberfest! The world's biggest Volkfest is held annually in Munich, Bavaria, Germany, with more than six million people from around the world attending.

The Challenge starts at 11:00 UTC and ends 5 days later on 26th September at 11:00 UTC. Work units from the AP27 project, which are downloaded and completed during the challenge will count towards your challenge score.

The last AP26 was found on 17th November 2018. Can we find an AP27 during the Challenge?

For more information and discussion, please head over to the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8764

Good luck!

2019-09-12: World Maths Day Challenge

Announcing a new Challenge slot! To celebrate World Maths Day, and our new PPS-DIV sub-project, we'll be running a 5 day Challenge from 10th October 18:00 UTC until 15th October 18:00 UTC. Other Challenge dates are unaffected.

The Fermat Divisor search is especially designed to have a better chance of finding a Fermat Divisor. It has a limited number of candidates to check, and once they're gone, the project is over. A new Fermat Prime Divisor earns the finder a rare badge. The project has found 18 primes so far, but no divisor.

For more information and discussion, read this forum thread or join our Discord server.

2019-09-11: World Record Generalized Cullen Prime

On 2 September 2019, 03:39:59 UTC, PrimeGrid?s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:

2805222*252805222+1

Generalized Cullen numbers are of the form: n*bn+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see ?Cullen prime? in The Prime Glossary.

The prime is 3,921,539 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 21st overall.

Base 25 was one of 11 primeless Generalized Cullen bases for b ?121 that PrimeGrid is searching. The remaining bases are 13, 29, 47, 49, 55, 69, 73, 101, 109 & 121.

The discovery was made by Tom Greer (tng*) of the United States using an Intel(R) Core(TM) i9-9900X CPU @ 3.50GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. His computer took 3 hours and 23 minutes to complete the primality test using multithreaded LLR. Tom is a member of the Sicituradastra team.

The prime was verified on 3 September 2019 05:15:11 UTC by Tim Terry (TimT) of the United States using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 24 hours 11 minutes to complete the primality test using multithreaded LLR. Tim is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2019-09-06: New Project: Fermat Divisor Search

PrimeGrid is proud to announce that we have a new sub-project, the Fermat Divisor search.

This is a variant of our other PPS (Proth Prime Search) sub-projects and is specially designed to have a better chance of finding a Fermat Divisor.

Unlike most of our other sub-projects, this one will not run forever. It has a limited number of candidates to check, and once they're gone, the project is over. My best guess is that this project will last about three months.

It uses the same badge and stats as the other PPS sub-projects, so there's no new badge. But this is probably the best chance of discovering a Fermat divisor and earning that rare badge.

For more information and discussion, read this forum thread or join our Discord server.

2019-08-22: Upcoming REQUIRED changes to app_config.xml

If you don't know what app_config.xml is, or if you don't use it for PrimeGrid's LLR apps, you can ignore this notice. This doesn't affect you.

But if you are using app_config.xml on any of our LLR apps, we are changing the plan class of the LLR app versions, and therefore your app_config.xml won't work after the changes. For details, as well as what you should do right now, please see this message. Comments, questions, and discussion are also located in that thread.

2019-08-07: Be careful with BOINC computers on the Internet

A lot of us use Cloud servers such as AWS, or make our home computers or our computers at work accessible on the Internet so we can control their BOINC clients remotely.

I was looking through the logs of some Azure servers I have running BOINC, and saw this on one of them:

10316 8/7/2019 11:39:23 AM GUI RPC request from non-allowed address 2.0.25.129
10648 8/7/2019 1:09:27 PM GUI RPC request from non-allowed address 2.0.42.193
10649 8/7/2019 1:09:27 PM 256 connections rejected in last 10 minutes

In fact, a similar address (somewhere in France, supposedly) tried to connect to the BOINC client on four of my BOINC machines. This has been happening since at least July.

If the BOINC client on your computers is accessible from the Internet, I advise putting your specific IP address (or addresses) into remote_hosts.cfg rather than leaving it open to the world, or doing the same in a firewall (or both). And use a strong password.

If you don't think this is important... anyone who successfully connects to the BOINC client on your computer can attach it to their own BOINC server, which can then send it tasks that can easily install malicious payloads such as key loggers, spam relays, DDOS bots, and other bad stuff.

EDIT: If this is all Greek to you and you don't know what I'm talking about, you're probably not at risk. BOINC starts off with remote access disabled. You have to explicitly go and change configuration files to enable remote access, and probably modify your firewall as well. If you haven't done that, you're okay.

2019-08-03: Lennart Vogel Honorary Challenge

To honour Lennart Vogel and his enormous contributions to Primegrid we're running a 7 day challenge from August 3rd 00:00 UTC until August 10th 00:00 UTC. Work units from the ESP (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

For more information and discussion, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8703

This one's for Lennart

2019-07-15: 50th Anniversary of the Moon Landing Challenge starts July 15th 20:17 UTC

"Thirty seconds and counting. Astronauts report it feels good. T-25 seconds. Twenty seconds and counting. T-15 seconds, guidance is internal. 12, 11, 10, 9 ... ignition sequence start ... 6, 5, 4, 3, 2, 1, 0 ... All engines running. Liftoff! We have a liftoff ... 32 minutes past the hour, liftoff on Apollo 11!"

To celebrate the 50th Anniversary of humans landing on the Moon, PrimeGrid is running a 5 day challenge from July 15th 2019, 20:17 UTC until July 20th, 20:17 UTC.

Work units from the PPS (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score. Many primes are expected to be found.

For more information and discussion, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8635

2019-07-08: GFN-524288 Mega Prime!

On 29 June 2019, 00:54:18 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2877652^524288+1

The prime is 3,386,397 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 26th overall.

The discovery was made by Roman Vogt (Tabaluga) of Germany using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-2700K CPU @ 3.50GHz CPU with 16GB RAM, running Windows 10. This GPU took about 1 hour and 42 minutes to probable prime (PRP) test with GeneferOCL5. Roman is a member of the Sicituradastra. team.

The PRP was verified on 29 June 2019, 08:52:47 by Carlo Villa (carlo) using an NVIDIA GeForce 830M in an Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz with 8GB RAM, running Windows 10. This GPU took about 16 hours and 55 minutes to probable prime (PRP) test with GeneferOCL5.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux. This computer took about 25 hours 53 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-06-28: Another New SR5 Mega Prime!

On 23 June 2019, 14:39:48 UTC, PrimeGrid?s Sierpi?ski/Riesel Base 5 Problem project eliminated k=322498 by finding the mega prime:

322498*5^2800819-1

The prime is 1,957,694 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 63rd overall and is the largest known base 5 prime. 67 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Jordan Romaidis of the United States using an Intel(R) Xeon(R) Gold 5120 CPU @ 2.20GHz with 96GB RAM running Microsoft Windows 10 Enterprise x64 Edition. This computer took 25 hours and 28 minutes to complete the primality test using multithreaded LLR. Jordan is a member of the San Francisco team.

The prime was verified on 24 June 2019, 20:59:33 UTC by Scott Brown of the United States using an AMD FX(tm)-8350 Eight-Core Processor with 16GB RAM running Microsoft Windows 10 Core x64 Edition. This computer took about 53 hours and 51 minutes to complete the primality test using multithreaded LLR. Scott is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2019-06-28: New SR5 Mega Prime!

On 21 June 2019, 01:30:42 UTC, PrimeGrid?s Sierpi?ski/Riesel Base 5 Problem project eliminated k=88444 by finding the mega prime:

88444*5^2799269-1

The prime is 1,956,611 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 63rd overall and is the largest known base 5 prime. 68 k?s now remain in the Riesel Base 5 problem.

The discovery was made by Scott Brown of the United States using an Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz with 32GB RAM running Microsoft Windows 10 Professional x64 Edition. This computer took 5 hours and 29 minutes to complete the primality test using multithreaded LLR. Scott is a member of the Aggie The Pew team.

The prime was verified on 21 June 2019, 14:50:01 UTC by Dave Sunderland (DaveSun) using an Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz with 16GB RAM running Microsoft Windows 10 Core x64 Edition. This computer took about 12 hours and 32 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-06-03: Scheduled Maintenance

We will be taking PrimeGrid offline for maintenance on Thursday, June 6th. If all goes well, the server will be down for less than an hour.

I'm not sure yet exactly when this will be done, but it's unlikely to start before 10:00 UTC.

While the server is down, you can keep up with status of the maintenance on our Discord server: https://discord.gg/N2mCaQz .

2019-05-23: Hans Ivar Riesel's 90th Birthday Challenge starts May 24th 2019 00:00 UTC

To celebrate Hans Ivar Riesel's birthday, PrimeGrid is having a 7 day challenge from May 24th 2019, 00:00 UTC until May 31st, 00:00 UTC.

Work units from the TRP (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

Help us celebrate, maybe find a really big prime number eliminating one of the Riesel k's for Riesel's birthday and earn a cool new badge!
Best estimate is 30% chance someone finds a prime during the challenge.

For more information and discussion, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8556

2019-05-22: AVX-512 Now Supported by LLR

All of PrimeGrid's LLR applications now support AVX-512 on CPUs with that capability. Those of you that have been using app_info.xml/anonymous platform to run LLR 3.8.23 may now use the stock app if you wish, which is also LLR 3.8.23.

UPDATE May 22nd: It has come to my attention that while CPUs with 2 AVX-512 execution units gain a substantial boost in performance, mid-range CPUs with only 1 AVX-512 execution unit may see a significant decrease in performance with the new LLR app. Obviously, this is not intended. For the time being there is no workaround for this. If you have a CPU that supports AVX-512, but has only a single AVX-512 execution unit, you may want to use the anonymous platform mechanism (app_info.xml) to run the older version of LLR. With a challenge starting tomorrow, we won't make changes to the app until at least a week. We apologize for any inconvenience this may cause.

UPDATE May 23rd: I've included a list of single and dual unit AVX-512 CPUs here.

2019-05-08: Reason you should upgrade BOINC

"If it ain't broke, don't fix it" isn't a terrible rule of thumb, but not in this case.

We've just updated most of PrimeGrid's apps, but to take advantage of them you'll need to be running a version of BOINC that isn't too ancient.

On the apps that use wrappers (currently all of the LLR apps and 321-Sieve) the priority of the wrapper is increased above idle priority. This may help avoid some infrequent crashes attributed to the wrapper. You'll need at least BOINC 7.4.0+ (first released in 2014) to take advantage of this feature. The LLR apps are already updated, and 321-Sieve will be updated in the near future.

All of the binary files will now be sent gzipped, which will reduce data transfer by about 50%. You'll need at least BOINC 7.0.0+ (first released in 2012) to take advantage of this feature.

If you're running a really old version of BOINC, you now have a reason to upgrade!

EDIT: There's been some confusion about how version numbers work. 7.14.2, released in October 2018, is the most recent version of BOINC as of right now, and is what you should be running. "14" comes after "4". 7.14.x is new, 7.4.x is quite old, and 7.0.x is even older!

2019-04-28: New SR5 Mega Prime!

On 26 April 2019, 13:27:42 UTC, PrimeGrid?s Sierpi?ski/Riesel Base 5 Problem project eliminated k=138514 by finding the mega prime:

138514*5^2771922+1

The prime is 1,937,496 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 63rd overall and is the largest known base 5 prime. 31 k?s now remain in the Sierpi?ski Base 5 problem.

The discovery was made by Ken Ito (jpldcon4) of Japan using an Intel(R) Core(TM) i9-9820X CPU @ 3.30GHz with 32 GB of RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took 2 hours and 46 minutes to complete the primality test using multithreaded LLR. Ken is a member of Team 2ch.

The prime was verified on 27 April 2019, 07:28:26 UTC by Dmitry Domanov (unconnected) of Russia using an Intel(R) Core(TM) i5-2310 CPU @ 2.90GHz with 3 GB of RAM, running Microsoft Windows XP Professional x86 Edition. This computer took about 23 hours and 24 minutes to complete the primality test using LLR. Dmitry is a member of the Russia team.

For more details, please see the official announcement.

2019-04-26: GFN-524288 Mega Prime!

On 17 Apr 2019, 11:00:27 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2788032^524288+1

The prime is 3,379,193 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 26th overall.

The discovery was made by Ed Goforth (BlisteringSheep) of the Netherlands Antilles using an NVIDIA GeForce GTX 760 in an Intel(R) Xeon(R) CPU E5-2687W v3 @ 3.10GHz CPU with 128GB RAM, running Linux. This GPU took about 3 hours 31 minutes to probable prime (PRP) test with GeneferOCL5. Ed is a member of the Christians team.

The prime was verified on 23 Apr 2019, 13:36:35 by Brent Schneider (KWSN-SpongeBob SquarePants) of Nepal using an NVIDIA GeForce GTX 1080 in an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Windows 10. This GPU took about 1 hour 17 minutes to probable prime (PRP) test with GeneferOCL5. Brent is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Windows 10. This computer took about 25 hours 4 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-04-22: GFN-17-MEGA Is Now GPU-ONLY

Effective immediately, CPU tasks for GFN-17-MEGA have been disabled. This project is now GPU-only.

The B-limit for the CPU x87 transform has been reached, and from this point on more and more GFN-17-MEGA tasks would fail on CPUs.

Only GFN-17-MEGA is affected. All of our other projects will continue operating as usual.

More discussion can be found here: https://www.primegrid.com/forum_thread.php?id=8558.

2019-04-10: GFN-524288 Mega Prime!

On 18 March 2019, 07:26:42 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2733014^524288+1

The prime is 3,374,655 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 26th overall.

The discovery was made by Yair Givoni of Israel using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz CPU with 16GB RAM, running Windows 10. This GPU took about 2 hours 57 minutes to probable prime (PRP) test with GeneferOCL3. Yair is a member of The Planetary Society team.

The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian. This computer took about 26 hours and 43 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2019-03-28: GCW Sieve is shutting down May 1st

This is the official 30 day warning.

On May 1st we will turn off the work generator for the GCW Sieve project. We expect all bases to have reached optimal sieving depth by then.

If you need extra credit for a badge or hours for WUProp, now is the time to get it.

For more information and discussion, please see this forum thread.

2019-03-05: Year of the Pig Challenge starts March 5th 2019 18:00 UTC

Gong hei fat choy! Wishing you great happiness and prosperity.
To celebrate the start of Chinese new year, PrimeGrid is having a 5 day challenge from March 5th 2019, 18:00 UTC until March 10th, 18:00 UTC.

Work units from the GCW (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

Help us celebrate, maybe find a really big prime number eliminating one of the Generalised Cullen bases and earn a cool new badge!

For more information and discussion, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8462

2019-02-23: Forum threads locked after a year

Effective immediately, forum threads will be automatically locked one year after the most recent post. If a thread has been inactive for a year, it's better to start a new thread than to reactivate a moribund thread.

If you need to reference something in the old thread, you can always link to the original post or thread using the [url]http://www.primegrid.com/something...[/url] tag.

2019-02-19: PrimeGrid and BOINC are looking for experienced Macintosh Developers

PrimeGrid is currently looking for a volunteer developer to build, test and maintain Mac apps. The current developer of PrimeGrid (and other applications that are used in the mathematics/prime search world) is no longer able to help us maintain the applications, which means that we may need to drop support for Macs over time (no such changes are planned right now or in the immediate future).

If you are able to help us, please don't hesitate to get in touch.


Moreover, the Berkeley Open Infrastructure for Network Computing (BOINC) open source project, which is the software infrastructure used by PrimeGrid and many other volunteer distributed computing projects, is also looking for volunteers to develop and maintain the BOINC client on Macintosh. The BOINC Client and Manager are C++ cross-platform code supporting MS Windows, Mac, Linux, and several other operating systems. BOINC currently has a number of volunteer developers supporting Windows and Linux, but their main Mac developer is winding down his involvement after many years. He is prepared to help a few new Mac developers get up to speed.

If you have Mac development experience and are interested in volunteering time to help support and maintain the BOINC Mac client please have a look at the more detailed description here: ?https://boinc.berkeley.edu/trac/wiki/MacDeveloper

If you are not a Mac developer, but have other skills and are interested in contributing to BOINC, the link above also has more general information.

2019-02-07: Tips for faster forums

If you find that loading forum messages is slow, there are two settings you can change on the Community Preferences page:

* Check the "Hide Badges" box. If you're not in Europe you probably have a ping time above 100 ms, and loading all those little badge images that everyone earns takes a while. Have you seen how many different badges people have? A tenth of a second for each one adds up.

* Check the "Show images as links" box. If a forum post contains an image from a third party site, including all badge or credit signature images, and that site is down or slow, it will significantly slow down loading the forum message page.

You can leave avatars and signatures turned on if you wish. They don't affect forum speed significantly.

2019-02-04: Feeling Lucky? World Record Prime Search Active Again

PrimeGrid now has a new project called "Do You Feel Lucky?" This is a world record prime search using GFN-22 with b starting at 846,398, which is the first b not removed by sieving where b^4194304+1 is greater than the current world record. Due to software limitations combined with the size of the numbers involved, this is a GPU-only project. The project will continue separate from the existing GFN22 search, and should the current world record increase, this project will be adjusted to then search beyond that new record.

For the full project details, please see this forum post.

So now "you've got to ask yourself one question: 'Do I feel lucky?' Well, do ya...?"

2019-01-30: 2019 Tour de Primes Starts February 1st!

Our annual Tour de Primes challenge begins in a little over one day from now, and runs for the entire month of February.

Unlike other challenges, you don't get a trophy just for participating -- you have to actually find primes to win something!

As with last year, we will be awarding special "jersey badges" to the winners in four different categories. We're also continuing the tradition of offering special badges that are available to anyone who finds an eligible prime!

Come join us in February. More information about Tour de Primes can be found here.

2019-01-06: Conjunction of Venus & Jupiter Challenge starts in 8 hours!

In about 8 hours, at 5:43:00 UTC January 7th, we kick off our 2019 challenge series with a 15 day SoB (Seventeen or Bust) challenge.

As with last year, the goal of this challenge is to accelerate the SoB double check. With a good challenge this year, we may be able to complete the double check in 2019!

More information and discussion about the challenge can be found in this forum thread.

2018-12-22: Another GFN-262144 Mega Prime!

On 14 December 2018, 07:07:34 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

6291332^262144+1

The prime is 1,782,250 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 10th for Generalized Fermat primes and 66th overall.

The discovery was made by Karsten Freihube (KFR) of Germany using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-4790 CPU at 3.60GHz with 16GB RAM, running Windows 10 Proffesional Edition. This GPU took about 35 minutes to probable prime (PRP) test with GeneferOCL2.

The prime was verified on 14 December 2018, 14:47:41 by Andreas Zenker (Buddy) of Austria Republic using an NVIDIA GeForce GTX 1060 GPU in an Intel(R) Core(TM)2 Quad CPU at 2.50GHz 4GB RAM, running Windows 7 Professional Edition. This GPU took about 42 minutes to probable prime (PRP) test with GeneferOCL2. Andreas is a member of Team PC-Reflate.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 4 hours 59 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-12-22: GFN-262144 Mega Prime!

On 12 December, 05:32:25 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

6287774^262144+1

The prime is 1,782,186 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 10th for Generalized Fermat primes and 66th overall.

The discovery was made by Greg Miller (Olgar) of the United States using an NVIDIA GeForce GTX 1050 in an AMD Phenom(TM) II x4 965 CPU with 16GB RAM, running Windows 10 Professional Edition. This GPU took about 60 minutes to probable prime (PRP) test with GeneferOCL2. Greg is a member of the USA team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 15 hours 44 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-12-10: Winter Solstice challenge starts tomorrow!

Tomorrow, December 11th, at 22:23 UTC, PrimeGrid's 10 day Winter Solstice Challenge will begin. The challenge ends on the moment of Winter Solstice itself, when the Earth's Northern pole has its maximum tilt away from the Sun and the Sun shines directly over the Tropic of Capricorn. Please join us in celebrating by crunching some GFN-21 tasks!

Details and discussion about the challenge can be found here: http://www.primegrid.com/forum_thread.php?id=8326.

2018-11-19: Substantial Planned Downtime Friday

This Friday, PrimeGrid is moving to new servers. Everything (except our Discord chat server) will be offline for several hours. Since the forums will be down, Discord will be the only way to communicate with us.

More information can be found on the forums here:
http://www.primegrid.com/forum_thread.php?id=7592&nowrap=true#122692

2018-11-17: Leonids Shower Challenge

From November 17th, 2018 Primegrid will be running an AP27 Challenge to celebrate the Leonid Meteor Shower. The Leonids are a prolific meteor shower associated with the comet Tempel?Tuttle. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky.

The Challenge starts at 12:00 UTC and ends 3 days later on 20th November at 12:00 UTC. Work units from the AP27 project, which are downloaded and completed during the challenge will count towards your challenge score.

An AP26 was found just before the start of the Challenge. Can we find an AP27?

For more information and discussion, please head over to the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8268

Good luck!

2018-11-10: Fix for Slow Forums

If you've been experiencing slow-loading forums at PrimeGrid, or, for that matter, any BOINC project's forums, the reason is because the Free-DC website has been down a lot recently.

Many people use forum signature images from Free-DC, which your browser loads when it displays forum messages. If Free-DC is down, your browser has to wait for the image request to Free-DC to time out. That's why the forum pages load slowly.

If you want forum pages to load more quickly, go to the Community Preferences page and check the "hide signatures" box. Don't forget to click on the "Update" button at the bottom.

2018-11-05: GFN-1048576 Mega Prime!

On 31 October 2018, 00:42:47 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1059094^1048576+1

The prime is 6,317,602 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat primes and 13th overall. This is the second-largest prime found by PrimeGrid, and the second-largest non-Mersenne prime.

The discovery was made by Rob Gahan (Robish) of Ireland using a Nvidia GeForce GTX 1080 in an Intel(R) Core(TM) i7-7820HK CPU at 2.90GHz with 32GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 3 hours 35 minutes to probable prime (PRP) test with GeneferOCL4. Rob is a member of the Storm team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 4 days, 5 hours, 54 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2018-11-04: New PrimeGrid Policy - Monetization of BOINC credit

PrimeGrid has decided not to participate in any system that monetizes our BOINC credit. For more details please see http://www.primegrid.com/forum_thread.php?id=8272.

2018-10-23: Halloween Challenge

Put on your costume and head out with your Treat Bag to enjoy Primegrid's Halloween Challenge. From October 24th, Primegrid will be running a spooky WoOOodall Challenge. The 7 day Challenge starts at 23:59:59 UTC and ends on 31st October one week later. Work units from the WOO (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

For more information and discussion, please head over to the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8222

BOO!

2018-10-22: 27 Mega Prime!

On 11 October 2018, 22:54:34, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search (k=27 sister project), has found the mega prime:

27*2^7046834+1

The prime is 2,121,310 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 48th overall.

The discovery was made by Andrew M. Farrow (Nortech) of Australia using an Intel(R) Xeon(R) CPU E3-1245 v6 @ 3.70GHz Processor with 16GB RAM, running Linux. This computer took about 1 hour 13 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-10-05: Restricted access to statistics files

Beginning October 12th, one week from today, access to the statistics files exported by PrimeGrid will be restricted to authorised statistics sites and other authorised users.

We're still working on the final plan, but if you are currently using our statistics files, please contact me either on the forums, by private message, or at the email address listed on our contacts page.

Michael Goetz

2018-10-01: GFN-262144 Mega Prime!

On 26 September 2018, 13:24:01 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

5828034^262144+1

The prime is 1,773,542 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 9th for Generalized Fermat primes and 66th overall.

The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-5930K CPU at 3.50GHz with 32GB RAM, running Windows 10 Core Edition. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL3. Rob is a member of the Storm team.

The prime was verified on 26 September 2018, 13:51:13 by Jan Kum?ta (Honza1616) of the Czech Republic using an NVIDIA GeForce GTX 1080 GPU in an AMD Ryzen 7 1700 CPU with 32GB RAM, running Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Jan is a member of the Czech National Team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 5 hours 57 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-09-28: Genefer 3.3.4 now live

The latest release of genefer (3.3.4) is now released on BOINC labelled as app version 3.20. The client will download the new app automatically, no action is required on your part unless you are using app_info.xml (if you don't know what this means, don't worry).

The new version provides a speed-up of around 10% for AVX and FMA3 transforms for n=21, as well as providing support for multithreading. To enable it, create an app_config.xml file in your BOINC/projects/www.primegrid.com directory containing (for 2 threads per task)




genefer
-nt 2
2
cpuGFN21




Any problems or questions, let us know! Please note that as the new release does not affect the OCL code, the GPU app versions remain unchanged.

2018-09-15: Oktoberfest Challenge!

From September 15th, 2018 Primegrid will be running a Cullen Challenge to celebrate Oktoberfest! The wold's biggest Volkfest is held annually in Munich, Bavaria, Germany, with more than six million people from around the world attending.

The 7 day Challenge starts at 18:00 UTC and ends on 22nd September exactly one week later at 18:00 UTC. Work units from the CUL (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

The last Cullen Prime found was 6679881*2^6679881+1 from 2009. We're now testing numbers past 16M, so emotionally due for a prime.

For more information and discussion, please head over to the official challenge thread: http://www.primegrid.com/forum_thread.php?id=8194

Good luck!

2018-08-22: New SR5 Mega Prime!

On 15 August 2018, 03:15:13 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=194368 by finding the mega prime:

194368*5^2638045-1

The prime is 1,843,920 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 60th overall and is the largest known base 5 prime. 69 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Honza Cholt (Honza) of the Czech Republic using an Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz with 20 GB RAM running Microsoft Windows Server 2016. This computer took about 4 hours 44 minutes to complete the primality test using multithreaded LLR. Honza is a member of the Czech National Team.

The prime was verified on 17 August 2018, 10:15:20 UTC by Deano Montreuil (Deano Montreuil) of the United States using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 8 GB RAM running Microsoft Windows 10 Core Edition. This computer took about 61 hours 55 minutes to complete the primality test using LLR. Deano is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2018-08-11: GFN-524288 Mega Prime!

On 4 August 2018, 09:10:53 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2312092^524288+1

The prime is 3,336,572 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat primes and 24th overall.

The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce GTX 690 in an Intel(R) Core(TM) i7-3930K CPU at 3.20GHz with 12GB RAM, running Windows 10 Professional Edition. This GPU took about 2 hours 36 minutes to probable prime (PRP) test with GeneferOCL5. Rob is a member of the Storm team.

The prime was verified on 4 August 2018, 23:28:14 UTC by Naoaki Tokuda (semanterion) of Japan using an NVIDIA Titan V in an Intel(R) Core(TM) i7-4960X CPU @ 3.60GHz with 64GB RAM, running Windows 7 Ultimate Edition. This GPU took about 24 minutes to probable prime (PRP) test with GeneferOCL5.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 20 hours 55 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-08-10: Solar Eclipse Challenge

August 11th, 2018 a partial solar eclipse will touch many countries in the Northern Hemisphere. We'll be running a Proth Prime Search (LLR) Challenge to celebrate.

The 3 day Challenge starts 10th August, 18:00 UTC and ends 13th August 2018, 18:00 UTC. Work units which are downloaded and completed during the challenge will count towards your challenge score. Many primes are expected to be found.

For more information, questions and friendly banter, please join us in this thread.

2018-08-01: Yet Another SR5 Mega Prime!

On 29 July 2018, 11:28:58 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=66916 by finding the mega prime:

66916*5^2628609-1

The prime is 1,837,324 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 59th overall and is the largest known base 5 prime. 70 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Honza Cholt (Honza) of the Czech Republic using an Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz with 32 GB RAM running Microsoft Windows 10 Professional Edition. This computer took about 4 hours 35 minutes to complete the primality test using multithreaded LLR. Honza is a member of the Czech National Team.

The prime was verified on 29 July 2018, 15:45:07 UTC by James Krauss (Grebuloner) of the United States using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16 GB RAM running Microsoft Windows 10 Professional Edition. This computer took about 5 hours 38 minutes to complete the primality test using multithreaded LLR. James is a member of The Knights Who Say Ni! team.

For more details, please see the official announcement.

2018-06-22: Another SR5 Mega Prime!

On 20 June 2018, 06:35:42 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=81556 by finding the mega prime:

81556*5^2539960+1

The prime is 1,775,361 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 61st overall. 32 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Ji?

2018-06-21: New SR5 Mega Prime!

On 19 June 2018, 09:48:29 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=327926 by finding the mega prime:

327926*5^2542838-1

The prime is 1,777,374 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 60th overall. 71 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Selya Tsuji (stsuji) of Japan using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 32 GB RAM running Microsoft Windows 10 Professional Edition. This computer took about 39 hours 37 minutes to complete the primality test using LLR. Selya is a member of Team 2ch.

For more details, please see the official announcement.

2018-06-19: Another GFN-262144 Mega Prime!

On 17 June 2018, 15:40:35 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

5205422^262144+1

The prime is 1,760,679 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 8th for Generalized Fermat primes and 60th overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an NVidia GeForce GTX 1080 in an Intel(R) Xeon(R) E5-1650 v3 CPU @ 3.50GHz with 32GB RAM, running Windows 7 Enterprise Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Scott is a member of the Aggie The Pew team.

The prime was verified on 17 June 2018, 16:44:04 UTC by Keith Reinhardt (Keith) of Canada using an NVidia GeForce GTX 1050 Ti in an Intel(R) Core(TM) i7-4790 CPU at 3.60GHz with 16GB RAM, running Windows 7 Professional Edition. This GPU took about 43 minutes to probable prime (PRP) test with GeneferOCL5. Keith is a member of the BOINC@Denmark team.

The PRP was confirmed prime by an Intel(R) Xeon(R) E3-1240 v6 CPU @ 3.70GHz with 2GB RAM, running Linux. This computer took about 5 hours 50 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2018-06-14: World Cup Challenge

Kick off for the first World Cup match is almost here, but we've started the World Cup Challenge on the SR5 (LLR) project. Come join us and see if you can score a goal!

5 day Challenge ends 19th June 2018, 00:00 UTC. Work units which are downloaded and completed during the challenge will count towards your challenge score.

For more information, questions and friendly banter, please join us in this thread. May the best team win!

2018-06-06: GFN-262144 Mega Prime!

On 5 June 2018, 05:24:10 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

5152128^262144+1

The prime is 1,759,508 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 8th for Generalized Fermat primes and 60th overall.

The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-5930K CPU at 3.50GHz with 32GB RAM, running Windows 10 Core Edition. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL3. Rob is a member of the Storm team.

The prime was verified on 5 June 2018, 05:43:47 by Aaron Houston Clinton (denim) of the United States using an NVIDIA GeForce GTX 1080 Ti GPU in an Intel(R) Core(TM) i7-6700K CPU at 4.00GHz with 16GB RAM, running Windows 10 Professional Edition. This GPU took about 13 minutes to probable prime (PRP) test with GeneferOCL3. Aaron is a member of the SETI.USA team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 7 hours 11 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-05-06: Do not use Nvidia driver 397.31

It has come to my attention that Nvidia recently released a new video driver that is causing widespread problems. 397.31 seems to cause the GPU to become inaccessible to both CUDA and OpenCL programs after a while, and can only be reset by rebooting the computer. It's likely this affects all BOINC projects and not just PrimeGrid. Indeed, it probably affects all GPU programs, even those that don't run under BOINC. There's a newer, hotfix driver 397.55 which seems to correct the problem. I strongly recommend either upgrading to 397.55 or rolling back to a driver earlier than 397.31.

More information can be found here.

2018-04-22: BOINC Pentathalon and Manual Credit

For two weeks next month, From May 5th until May 19th, the annual BOINC Pentathalon will be happening. In the past PrimeGrid has been fortunate to be chosen as one of the disciplines, and we're once again in the running for this year's Pentathalon.

It has come to our attention that our manual credit system has been used in the past to try and game the Pentathalon's scoring system. We've also noticed several people who seem to be planning on doing that this year.

We don't like cheaters. Neither do most of you. We believe in providing a level playing field. In order to both prevent cheating and to discourage people from even trying, we will be turning off the manual credit system during the Pentathalon. You'll still be able to earn manual credit during the Pentathalon, but it won't be applied until after the 19th.

All this is predicated on PG being part of the Pentathlon. If not, it doesn't matter. But for the purposes of argument we're assuming we will be.

The discussion thread for this topic is located here.

2018-04-22: BOINC Pentathlon and Manual Credit

For two weeks next month, From May 5th until May 19th, the annual BOINC Pentathlon will be happening. In the past PrimeGrid has been fortunate to be chosen as one of the disciplines, and we're once again in the running for this year's Pentathlon.

It has come to our attention that our manual credit system has been used in the past to try and game the Pentathlon's scoring system. We've also noticed several people who seem to be planning on doing that this year.

We don't like cheaters. Neither do most of you. We believe in providing a level playing field. In order to both prevent cheating and to discourage people from even trying, we will be turning off the manual credit system during the Pentathlon. You'll still be able to earn manual credit during the Pentathlon, but it won't be applied until after the 19th.

All this is predicated on PG being part of the Pentathlon. If not, it doesn't matter. But for the purposes of argument we're assuming we will be.

The discussion thread for this topic is located here.

2018-04-17: New LLR apps

We have upgraded the version of LLR used on all of our LLR projects to LLR v.3.8.21.

As with the previous version of LLR, it is available in 32 and 64 bit versions for Windows and Linux, and 64 bits for Mac OS.

This release has two major features:

* Support for AVX/FMA3 on AMD Ryzen CPUs. You can expect about a 10% increase in speed on Ryzen processors as compared to earlier versions of LLR.

* A rare bug that sometimes caused errors when using multithreading has been corrected.

If you are using app_info.xml (aka anonymous platform) please upgrade to the latest LLR. The wrapper is unchanged. Upgrading is not mandatory, but is strongly recommended.

If you are not using app_info.xml, you will automatically get the new version with your next LLR task and no action is necessary on your part. If you're not sure if you're using app_info.xml you're almost certainly not using it, and no action is necessary.

2018-04-05: ESP Mega Prime!

On 3 April 2018, 15:55:55 UTC, PrimeGrid?s Extended Sierpinski Problem Prime Search project found the Mega Prime:
193997*2^11452891+1

The prime is 3,447,670 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 23th overall. This find eliminates k=193997; 10 k's remain in the Extended Sierpinski Problem.

The discovery was made by Tom Greer (tng*) of the United States using an Intel(R) Xeon(R) E5-2620 v3 CPU @ 2.40GHz with 16GB RAM, running Microsoft Windows 10. This computer took about 3 hours 45 minutes to complete the primality test using multithreaded LLR. Tom is a member of the Sicituradastra. team.

The prime was verified on 4 April 2018, 00:17:20 UTC by Gary Bauer (GDB) of the United States using an Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz with 16GB RAM, running Microsoft Windows 10. This computer took about 2 hours 25 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2018-04-02: Mathematics Awareness Month Challenge Starts April 3rd at 12:00 UTC

To help celebrate Mathematics Awareness Month we will be running a 5 day challenge on the ESP (LLR) sub-project.

Starts April 3rd 12:00:00 UTC and finishes April 8th 12:00:00 UTC.

The last prime found on this sub-project was 161041*2^7107964+1 on 6th January 2015. We're now searching n > 11,313,676.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7935

2018-04-01: World Record Woodall Prime!

On 21 March 2018, 22:13:39 UTC, PrimeGrid?s Woodall Prime Search found the Woodall mega prime:

17016602*2^17016602-1

Woodall numbers are of the form: W(n)=n*2^n-1. Woodall numbers that are prime are called Woodall primes. For more information, please see ?Woodall prime? in The Prime Glossary (http://primes.utm.edu/glossary).

The prime is 5,122,515 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Woodall primes and 16th overall. This is the 4th largest prime found by PrimeGrid, the 4th Woodall prime found by PrimeGrid, and the first Woodall prime found since December, 2007.

The discovery was made by Diego Bertolotti (ScOrPIoN) of Italy using an Intel(R) Core(TM) i7-2600 CPU at 3.40GHz with 8GB RAM, running Microsoft Windows 10. This computer took about 4 days 6 hours 14 minutes to complete the primality test. Diego is a member of the Boinc @ Italy team.

For more details, please see the official announcement.

2018-03-28: GFN-524288 Mega Prime!

On 20 March 2018, 08:28:32 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2061748^524288+1

The prime is 3,310,478 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat primes and 22nd overall.

The discovery was made by Cesare Marini (Cesare Marini) of Italy using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-6700 CPU at 3.40GHz with 32GB RAM, running Windows 10 Professional Edition. This GPU took about 1 hour 32 minutes to probable prime (PRP) test with GeneferOCL5.

The prime was verified on 20 March 2018, 19:46:06 UTC by H

2018-03-17: Another World Record Generalized Cullen Prime!

On 11 March 2018, 23:54:40 UTC, PrimeGrid?s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:

1806676*41^1806676+1

Generalized Cullen numbers are of the form: n*b^n+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see ?Cullen prime? in The Prime Glossary.

The prime is 2,913,785 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 27th overall.

Base 41 was one of 12 prime-less Generalized Cullen bases below b=121 that PrimeGrid is searching. The remaining bases are 13, 25, 29, 47, 49, 55, 69, 73, 101, 109 & 121.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) Xeon(R) E5-2670 CPU @ 2.60GHz with 4GB RAM, running Linux. This computer took about 7 hours and 13 minutes to complete the primality test using multithreaded LLR. Hiroyuki is a member of the Aggie The Pew team.

The prime was verified on 12 March 2018 09:07:23 UTC by Scott Brown (Scott Brown) of the United States using an Intel(R) CPU @ 2.30GHz with 16GB RAM, running Windows 10 Professional Edition. This computer took about 15 hours 22 minutes to complete the primality test using LLR. Scott is also a member of the Aggie The Pew team.

For more details, please see the official announcement.

2018-03-16: Year of the Dog Challenge starts March 16th 2018 18:00 UTC

To celebrate the start of Chinese new year, PrimeGrid is hosting a 7 day challenge from March 16th 2018, 18:00 UTC until March 23rd, 18:00 UTC.

Work units from the 321 (LLR) project, which are downloaded and completed during the challenge will count towards your challenge score.

For more information, questions and chit chat concerning this challenge, please join us in this thread. And as always we hope to see you there and feel free to spread the word.

2018-03-03: GFN-262144 Mega Prime!

On 1 March 2018, 04:16:07 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

4489246^262144+1

The prime is 1,743,828 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 7th for Generalized Fermat primes and 56th overall.

The discovery was made by Wolfgang Schwieger (DeleteNull) of Germany using an NVIDIA GeForce GTX 1070 Ti in an Intel(R) CPU at 2.30GHz with 32GB RAM, running Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Wolfgang is a member of the SETI.Germany team.

The prime was verified on 1 March 2018, 04:28:47 by Jonathan Sipes (k4m1k4z3) of the United States using an NVIDIA GeForce GTX 1080 GPU in an Intel(R) Core(TM) i7-2700K CPU at 3.50GHz with 8GB RAM, running Windows 7 Professional Edition. This GPU took about 20 minutes to probable prime (PRP) test with GeneferOCL3. Jonathan is a member of the Overclock.net team.

The PRP was confirmed prime by an Intel(R) Xeon(R) E3-1240 v6 CPU @ 3.70GHz with 2GB RAM, running Linux. This computer took about 5 hours 33 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-02-19: GFN-262144 Mega Prime!

On 15 February 2018, 02:15:40 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

4246258^262144+1

The prime is 1,737,493 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 7th for Generalized Fermat primes and 57th overall.

The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce Titan X in an Intel(R) Core(TM) i7-5930K CPU at 3.50GHz with 32GB RAM, running Windows 10 Core Edition. This GPU took about 23 minutes to probable prime (PRP) test with GeneferOCL3. Rob is a member of the Storm team.

The prime was verified on 15 February 2018, 02:18:23 by Daniel Fru?y?ski ([B@P] Daniel) of Poland using an NVIDIA GeForce GTX 1070 GPU in an Intel(R) Core(TM) i7-2600K CPU at 3.40GHz with 16GB RAM, running Windows 10 Professional Edition. This GPU took about 20 minutes to probable prime (PRP) test with GeneferOCL3. Daniel is a member of the BOINC@Poland team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 4 hours 37 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-01-31: GFN-15 CPU tasks are disabled!

We've reached the B limit for the CPU version of Genefer on n=15. As a result, at least temporarily, no more CPU tasks will be sent out on GFN-15. GPU tasks are unaffected and are still available. For more information and discussion, please see this forum thread.

2018-01-30: 2018 Tour de Primes begins February 1st!

Our annual Tour de Primes challenge begins in a little over one day from now, and runs for the entire month of February.

Unlike other challenges, you don't get a trophy just for participating -- you have to actually find primes to win something!

As with last year, we will be awarding special "jersey badges" to the winners in four different categories. This year, we're also offering special badges that are available to anyone who finds an eligible prime!

Come join us in February. More information about Tour de Primes can be found here.

2018-01-30: GFN-262144 Mega Prime!

On 27 January 2018, 20:06:08 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3933508^262144+1

The prime is 1,728,783 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 7th for Generalized Fermat primes and 57th overall.

The discovery was made by Alen Kecic (freezing) of Germany using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-7820X CPU at 3.60GHz with 32GB RAM, running Windows 10 Professional Edition. This GPU took about 26 minutes to probable prime (PRP) test with GeneferOCL3. Alen is a member of the SETI.Germany team.

The prime was verified on 29 January 2018, 20:09:57 by Arne Sielemann ([SG-FC] dingdong) of Germany using an AMD R9 290/HD 7900 (Tahiti) series GPU in an Intel(R) Core(TM) i7-3770K CPU at 3.50GHz with 16GB RAM, running Windows 10 Core Edition. This GPU took about 56 minutes to probable prime (PRP) test with GeneferOCL5. Arne is a member of the SETI.Germany team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 4 hours 33 minutes to complete the primality test using LLR.

For more details please see the official announcement.

2018-01-24: GFN-524288 Mega Prime!

On 15 January 2018, 01:27:20 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1880370^524288+1

The prime is 3,289,511 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat primes and 22nd overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i7-2600 CPU at 3.40GHz with 8GB RAM, running Windows 10 Core Edition. This GPU took about 2 hours 27 minutes to probable prime (PRP) test with GeneferOCL4. Scott is a member of the Aggie The Pew team.

The prime was verified on 15 January 2018, 13:47:11 UTC by user tangwei@CN of China using an NVIDIA GeForce GTX 1070 in an Intel(R) Xeon(R) E3-1230v2 CPU @ 3.30GHz with 8GB RAM, running Windows 10 Professional Edition. This GPU took about 59 minutes to probable prime (PRP) test with GeneferOCL4. Tangwei@CN is a member of Team China.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 20 hours 40 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2018-01-20: World Record Generalized Cullen Prime!

On 18 January 2018, 19:39:18 UTC, PrimeGrid?s Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:

1323365*116^1323365+1

Generalized Cullen numbers are of the form: n*b^n+1. Generalized Cullen numbers that are prime are called Generalized Cullen primes. For more information, please see ?Cullen prime? in The Prime Glossary (http://primes.utm.edu/glossary/xpage/Cullens.html).

The prime is 2,732,038 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 30th overall.

Base 116 was one of 13 prime-less Generalized Cullen bases below b=121 that PrimeGrid is searching. The remaining bases are 13, 25, 29, 41, 47, 49, 55, 69, 73, 101, 109 & 121.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4770S CPU @ 3.10GHz with 4GB RAM, running Windows 10 Enterprise Edition. This computer took about 8 hours and 34 minutes to complete the primality test using multithreaded LLR. Scott is a member of the Aggie The Pew team.

The prime was verified on 19 January 2018 17:24:17 UTC by Serge De Saffel (lentosy) of Belgium using an Intel(R) Core(TM) i5-6600K CPU @ 3.50GHz with 16GB RAM, running Windows 10 Education Edition. This computer took about 15 hours 22 minutes to complete the primality test using LLR. Serge is a member of the team Sicituradastra.

For more details, please see the official announcement.

2018-01-12: GFN-262144 Mega Prime!

On 10 January 2018, 12:26:12 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3853792^262144+1

The prime is 1,726,452 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 6th for Generalized Fermat primes and 55th overall.

The discovery was made by Rod Skinner (rjs5) of the United States using an NVIDIA GeForce GTX 1080 in an Intel(R) Core(TM) i7-8700K CPU at 3.70GHz with 16GB RAM, running Linux. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Rod is a member of the Intel Corporation team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 6 hours 59 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-12-29: PPS-Mega Prime!

On 28 December 2017, 05:55:36 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1155*2^3455254+1

The prime is 1,040,139 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 209th overall.

The discovery was made by Josh Closs (Josh Closs) of the United States using an Intel(R) Core(TM) i5-6400 CPU @ 2.70GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 57 minutes to complete the primality test using LLR. Josh is a member of the Crunch Squad team.

The prime was verified on 29 December 2017, 12:08:17 UTC by Howard Gordon ([PST]Howard) of the United Kingdom using an AMD Ryzen 7 1800X CPU with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 1 hour 30 minutes to complete the primality test using LLR. Howard is a member of the PrimeSearchTeam team.

For more details, please see the official announcement.

2017-12-28: PrimeGrid's Happy New Year's Challenge!

At the stroke of midnight (UTC) on New Year's day, PrimeGrid is starting off our 2018 Challenge series with our Seventeen or Bust Happy New Year's Challenge!

This 15 day challenge is intended to speed up our ongoing double check of older SoB tests that were never checked to see if the initial results were correct. Could there be a missed prime in there somewhere? It's certainly possible -- two of the 12 primes found so far in the SoB effort were in fact discovered during previous double check efforts.

Help us celebrate the new year, and maybe find a really, really big prime number as well as eliminating one of the five remaining k's in the Sierpinski Problem.

For more information and discussion, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7767

2017-12-17: Winter Solstice challenge starts tomorrow!

Tomorrow, December 18th, at 16:28 UTC, PrimeGrid's three day Winter Solstice Challenge will begin. Please join us in celebrating the Winter Solstice by crunching some PPS-Sieve tasks!

Details and discussion about the challenge can be found here: http://www.primegrid.com/forum_thread.php?id=7721.

2017-12-15: TRP Mega Prime!

On 13 December 2017, 07:13:55 UTC, PrimeGrid?s The Riesel Problem project eliminated k=273809 by finding the mega prime:

273809*2^8932416-1

The prime is 2,688,931 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 29th overall. This is PrimeGrid's 15th elimination. 49 k's now remain.

The discovery was made by Wolfgang Schwieger (DeleteNull) of Germany using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 32 GB RAM running Linux. This computer took about 2 hours and 14 minutes to complete the primality test using multithreaded LLR. Wolfgang is a member of the SETI.Germany team.

The prime was verified on 15 December 2017, 11:39:55 UTC, by Christian Geffcken (CGe0963) of Switzerland using an Intel(R) Core(TM) i5-3437U CPU @ 1.90GHz with 8 GB RAM running Microsoft Windows 7 Professional. This computer took about 41 hours and 47 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-12-05: Another PPS-Mega Prime!

On 3 December 2017, 20:54:51 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1065*2^3447906+1

The prime is 1,037,927 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 210th overall.

The discovery was made by Juan C. Toledo (Meithan West) of Mexico using an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 8GB RAM, running Linux. This computer took about 1 hour 48 minutes to complete the primality test using LLR. Juan is a member of the UNAM ? Universidad Nacional Autonoma de Mexico team.

The prime was verified on 3 December 2017, 22:23:34 UTC by Lucas Brown (LucasBrown) of the United States using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 64GB RAM, running Linux. This computer took about 48 minutes to complete the primality test using LLR. Lucas is a member of the XKCD team.

For more details, please see the official announcement.

2017-12-04: GFN-262144 Mega Prime!

On 3 December 2017, 06:30:24 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3673932^262144+1

The prime is 1,721,010 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 6th for Generalized Fermat primes and 53rd overall.

The discovery was made by Sean Humphries (No.15) of the United States using an AMD Radeon RX Vega in an AMD Ryzen 7 1800X CPU with 32GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 24 minutes to probable prime (PRP) test with GeneferOCL5. Sean is a member of the Overclock.net team.

The prime was verified on 3 December 2017, 07:29:36 UTC by Wolfgang Schwieger (DeleteNull) of Germany using an NVidia GeForce GTX Titan Black GPU in an Intel(R) Core(TM) i7-6700K CPU at 4.00GHz with 32GB RAM, running Linux. This GPU took about 27 minutes to probable prime (PRP) test with GeneferOCL5. Wolfgang is a member of the SETI.Germany team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 5 hours 45 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2017-11-28: PPS-Mega Prime!

On 27 November 2017,15:53:16 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1155*2^3446253+1

The prime is 1,037,429 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 209th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 8 minutes to complete the primality test using LLR.

The prime was verified on 27 November 2017, 16:01:56 UTC by John S. Chambers (Johnny Rotten) of the United States using an Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz with 16GB RAM, running Microsoft Windows 10. This computer took about 35 minutes to complete the primality test using multithreaded LLR. John is a member of the SETI.USA team.

For more details, please see the official announcement.

2017-11-20: GFN-262144 Mega Prime!

On 16 November 2017, 15:38:45 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3596074^262144+1

The prime is 1,718,572 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 6th for Generalized Fermat primes and 53rd overall.

The discovery was made by Howard Gordon ([PST]Howard) of the United Kingdom using a Nvidia GeForce GTX 1060 in an AMD Ryzen 1950X with 32GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 30 minutes to probable prime (PRP) test with GeneferOCL3. Howard is a member of the PrimeSearchTeam team.

Double-checker information will be provided once available.

The PRP was confirmed prime by an Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz with 24GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 10 hours 10 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2017-11-17: Pierre de Fermat's Birthday Challenge in 12 hours!

In less than 12 hours, PrimeGrid's three day Pierre de Fermat's Birthday Challenge will begin. For the first time ever, this challenge will feature the three smallest Generalized Fermat projects, GFN-15, GFN-16, and GFN-17-Low.

Head on over to the the challenge's forum thread for more information and discussion.

Good luck!

2017-11-14: Announcing: Fewer Announcements!

In 2018, we are changing our policies regarding announcement of significant prime discoveries. We're raising the bar so that announcements once again are something special and not just "the prime of the week."

Details and discussion can be found here.

2017-11-14: Another PPS-Mega Prime!

On 13 November 2017, 00:26:44 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
943*2^3442990+1

The prime is 1,036,447 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 208th overall.

The discovery was made by Joshua Charles Campbell (Warp Zero) of Canada using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 64GB RAM, running Linux. This computer took about 42 minutes to complete the primality test using multithreaded LLR. Joshua is a member of the Canada team.

The prime was verified on 13 November 2017, 18:22:32 UTC by Jon Goral ([KWSN]John Galt 007) of the United States using an Intel(R) Core(TM) i7 940 CPU @ 2.93GHz with 24GB RAM, running Microsoft Windows 10. This computer took about 6 hour 76 minutes to complete the primality test using LLR. Jon is a member of The Knights Who Say Ni! team.

For more details, please see the official announcement.

2017-11-03: Another PPS-Mega Prime!

On 2 November 2017, 16:43:22 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
943*2^3440196+1

The prime is 1,035,606 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 208th overall.

The discovery was made by Luk

2017-11-01: GFN-262144 Mega Prime!

On 30 October 2017, 01:31:18 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3547726^262144+1

The prime is 1,717,031 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 6th for Generalized Fermat primes and 53rd overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using a Nvidia GeForce GTX 1080 Ti in an Intel(R) Xeon(R) E5-1650 v3 CPU at 3.50GHz with 32GB RAM, running Microsoft Windows 7 Enterprise Edition. This GPU took about 17 minutes to probable prime (PRP) test with GeneferOCL3. Scott is a member of the Aggie The Pew team.

The prime was verified on 30 October 2017, 11:31:11 UTC by Alexander Falk (Alexander Falk) of the United States using an NVidia GeForce GTX 1080 GPU in an Intel(R) Core(TM) i7-7700K CPU at 4.20GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Alexander is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz with 24GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 12 hours 30 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2017-10-30: And Yet Another PPS-Mega Prime!

On 29 October 2017, 18:33:36 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
543*2^3438810+1

The prime is 1,035,188 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 207th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz with 8GB RAM, running Windows 10 Enterprise Edition. This computer took about 1 hour 48 minutes to complete the primality test using LLR.

The prime was verified on 30 October 2017, 04:48:03 UTC by Pete Allivato (Todderbert) of the United States using an Intel(R) Xeon(R) E31240 CPU @ 3.30GHz with 8GB RAM, running Windows 7 Professional Edition. This computer took about 1 hour 27 minutes to complete the primality test using LLR. Pete is a member of the GPU Users Group team.

For more details, please see the official announcement.

2017-10-30: Yet Another PPS-Mega Prime!

On 27 October 2017, 22:42:37 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
625*2^3438572+1

The prime is 1,035,117 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 207th overall.

The discovery was made by Jochen Beck (dh1saj) of Germany using an Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz with 32GB RAM, running Windows 10 Professional Edition. This computer took about 51 minutes to complete the primality test using LLR. Jochen is a member of the SETI.Germany team.

The prime was verified on 27 October 2017, 22:48:56 UTC by Lars Fricke (Lars Fricke) of Germany using an Intel(R) Xeon(R) E5-2620 v4 CPU @ 2.10GHz with 64GB RAM, running Linux. This computer took about 1 hour 29 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-10-18: Another PPS-Mega Prime!

On 17 October 2017, 13:48:48 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1147*2^3435970+1

The prime is 1,034,334 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 208th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 6 minutes to complete the primality test using LLR.

The prime was verified on 17 October 2017, 14:57:02 UTC by Amy Chambers (Buckeye74) of the United States using an Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 1 hour 13 minutes to complete the primality test using LLR. Amy is a member of the Sigma Omicron Chapter of Tau Kappa Epsilon team.

For more details, please see the official announcement.

2017-10-17: Diwali/Deepavali Challenge Starts Today!

Please note the start time of this challenge: 00:00:00

This is 18 hours earlier than usual. Don't be late!

Help us celebrate Diwali/Deepavali by participating in our 5 day challenge on the Riesel Problem LLR sub-project.

The challenge starts at 00:00:00 UTC tomorrow, October 18th (that's about 7 hours from now), and ends in 5 days at 00:00:00 UTC on October 23rd.

The last prime eliminating a k in the Riesel Problem was found on October 4th, 2014 -- just over three years ago!

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7623

2017-10-09: Another PPS-Mega Prime!

On 5 October 2017, 08:47:45 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
911*2^3432643+1

The prime is 1,033,331 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 208th overall.

The discovery was made by Jochen Beck (dh1saj) of Germany using an Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz with 8GB RAM, running Windows 7 Professional Edition. This computer took about 1 hour 25 minutes to complete the primality test using LLR. Jochen is a member of the SETI.Germany team.

The prime was verified on 6 October 2017, 22:29:00 UTC by Georgios Magklaras (georgios) of Greece using an Intel(R) Xeon(R) E5-2650 v3 CPU @ 2.30GHz with 128GB RAM, running Linux. This computer took about 2 hours 28 minutes to complete the primality test using LLR. Georgios is a member of the Team Norway team.

For more details, please see the official announcement.

2017-10-05: PRPNet server set to "No New Work"

As part of our upcoming server move, effective immediately PRPNet will not be giving out new work. Jobs in progress can still be returned for credit, but no more new tasks will be sent out from the server.

This only affects the PRPNet server. The BOINC server is not affected by this change.

Please see this thread for more information and discussion.

2017-09-29: New SR5 Mega Prime!

On 17 September 2017, 20:18:24 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=301562 by finding the mega prime:

301562*5^2408646-1

The prime is 1,683,577 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 57th overall. 72 k's now remain in the Riesel Base 5 Problem.

The discovery was made by H

2017-09-29: New PSP Mega Prime!

On 17 September 2017, 21:30:08 UTC, PrimeGrid?s Prime Sierpinski Problem project eliminated k=168451 by finding the mega prime:

168451*2^19375200+1

The prime is 5,832,522 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 13th overall. 9 k's now remain in the Prime Sierpinski Problem (2 of which are being searched as part of Seventeen or Bust). This is the third largest prime found by PrimeGrid.

Until the Prime Sierpinski Project shut down in 2014, this search was a collaboration between Primegrid and the Prime Sierpinski Project. This discovery would not have been possible without all the work done over the years by the Prime Sierpinski Project.

The discovery was made by Ben Maloney (paleseptember) of Australia using an Intel(R) Core(TM) i5-6400 CPU @ 2.70GHz with 16GB RAM running Windows 10 Professional Edition. This computer took about 2 days, 15 hours, 11 minutes to complete the primality test using LLR. Ben is a member of the Free-DC team.

The prime was verified on 23 September 2017 00:58:27 UTC by user cnoize using an Intel(R) Xeon(R) E5-2640 CPU @ 2.50GHz with 8GB RAM, running Windows Server 2008R2. This computer took about 6 days, 7 hours, 19 minutes to complete the primality test using LLR. Cnoize is a member of Team China, and the system was participating in the Gridcoin team.

For more details, please see the official announcement.

2017-09-23: GFN-131072 Mega Prime!

On 14 September 2017, 23:21:44 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

47179704^131072+1

The prime is 1,005,815 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 26th for Generalized Fermat primes and 250th overall.

The discovery was made by Andrei Okhrimouk (AndreiO) of Australia using an NVIDIA Geforce GTX 960 series GPU in an Intel(R) Core(TM)2 Duo CPU at 2.80GHz with 4GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 21 minutes to probable prime (PRP) test with GeneferOCL2.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 7 Ultimate Edition. This computer took about 2 hours 42 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2017-09-22: PRPNet September Challenge

Factorial Equinox Challenge

The equinoxes are the only times when the solar terminator (the "edge" between night and day) is perpendicular to the equator. As a result, the northern and southern hemispheres are equally illuminated. The Latinate names vernal equinox (spring) and autumnal equinox (fall) are often used. To celebrate we're running a PRPNet challenge at the FPS (factorial prime search) from 22nd 12:00 UTC until 27th of September 12:00 UTC.
To take part, you have to activate the following line in prpclient.ini:
server=FPS:100:1:prpnet.primegrid.com:12002
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2017 PRPNet September Challenge.

Good luck!

2017-09-16: Another PPS-Mega Prime!

On 15 September 2017, 11:01:15 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1127*2^3427219+1

The prime is 1,031,699 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 203rd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 6GB RAM, running Linux. This computer took about 1 hour 13 minutes to complete the primality test using LLR.

The prime was verified on 15 September 2017, 22:09:16 UTC by Hans-J

2017-09-15: We Need Your Help!

In the past, donations were nice to have, but not critical to our operation. As you likely already know, RackSpace is ending our free hosting. While all of the PrimeGrid admins volunteer their effort, equipment, and electricity, as do all of its members, PrimeGrid needs to find and afford a home.

In choosing a path forward, we have considered both current and ongoing costs, as well as maintaining quality of service at the levels to which we've become accustomed. In doing so, the best option for PrimeGrid is to purchase servers and house them at a paid colocation service.

Moving forward, PrimeGrid needs to cover the 3,500 euro cost of the initial hardware purchase, and then needs to start covering the costs of colocation. Ultimately, we will need to plan for hardware lifecycle as well. We are quite appreciative of the donations we have received towards this effort, and you can see our progress here: https://www.primegrid.com/donations.php where it quickly becomes evident that we still have a ways to go.

Your contributions are greatly appreciated and will help keep PrimeGrid strong and viable in the years ahead. We have done a lot of great work here, and hope to ensure its continued success.

2017-09-07: AP26 Found!

On 5 September 2017, 08:23:41 UTC, PrimeGrid?s AP27 Search (Arithmetic Progression of 27 primes) found the progression of 26 primes:

48277590120607451+37835074*23#*n for n=0..25

It is the 7th known AP26 known to exist, and the fourth found at PrimeGrid.

The discovery was made by Bruce E. Slade (Renix1943) of the United States using a NVIDIA GTX 970 GPU in an Intel(R) Core(TM) i3-6100 @ 3.70GHz CPU with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 41 minutes to process the task (each task tests 100 progression differences of 10 shifts each). Bruce is a member of the Aggie The Pew team.

The progression was verified on 5 September 2017 19:34:24 UTC, by Axel Schneider (axels) of Germany using an NVIDIA GTX 680 GPU on an Intel(R) Core(TM)2 Quad Q9400 CPU @ 2.66GHz with 8GB RAM running Microsoft Windows 7 Home Premium Edition. This computer took about 2 hours 6 minutes to process the task. Axel is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-09-02: GFN-1048576 Mega Prime!

On 29 August 2017, 14:15:23 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

919444^1048576+1

The prime is 6,253,210 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat primes and 12th overall. This is the first Generalized Fermat prime found for n=20, the second-largest prime found by PrimeGrid, and the second-largest non-Mersenne prime.

The discovery was made by Sylvanus A. Zimmerman (Van Zimmerman) of the United States using a Nvidia GeForce GTX 1060 in an Intel(R) Xeon(R) E3-1225 v3 CPU at 3.20GHz with 8GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 4 hours 43 minutes to probable prime (PRP) test with GeneferOCL4. Sylvanus is a member of the Aggie The Pew team.

Double-checker information will be announced once available.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 3 days, 23 hours, 53 minutes to complete the primality test using multithreaded LLR.

For more details, please see the official announcement.

2017-09-01: GFN-131072 Mega Prime!

On 30 August 2017, 13:17:35 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

47090246^131072+1

The prime is 1,005,707 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 24th for Generalized Fermat primes and 247th overall.

The discovery was made by Roman Voskoboynikov (rvoskoboynikov) of the United States using a Nvidia GeForce GTX 1050 Ti in an Intel(R) Core(TM) i5-4670 CPU at 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 16 minutes to probable prime (PRP) test with GeneferOCL2.

The prime was verified on 30 August 2017, 16:23:08 UTC by Ulrich Hartel (Uli2*) of Germany using an NVidia GeForce GTX 970M GPU in an Intel(R) Core(TM) i7-4720Q CPU with 16GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 16 minutes to probable prime (PRP) test with GeneferOCL2. Ulrich is a member of the Sicituradastra. team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 7 Ultimate Edition. This computer took about 2 hours 38 minutes to complete the primality test using multicore LLR.

For more details please see the official announcement.

2017-09-01: Number Theory Week Challenge Starts September 3rd at 18:00 UT

To help celebrate Number Theory Week we will be running a 5 day challenge on the 321 Prime Search (LLR) sub-project.

Starts September 3rd 18:00:00 UTC and finishes September 8th 18:00:00 UTC.

The last prime found on this sub-project was 3*2^11895718-1 on 23rd June 2015. We're now searching n > 13210424.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7575

2017-08-28: SR5 Mega Prime!

On 25 August 2017, 04:39:57 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=171362 by finding the mega prime:

171362*5^2400996-1

The prime is 1,678,230 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 57th overall. 73 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Frank Schwegler (Frank Schwegler) of the United States using an Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz with 16GB RAM running Microsoft Windows 7 Ultimate Edition. This computer took about 40 hours 12 minutes to complete the primality test using LLR.

The prime was verified on 26 August 2017 04:44:17 UTC by Sam Omlotek (SamO) of the United States using an Intel(R) Core(TM) i5-2500S CPU @ 2.70GHz with 8GB RAM, running macOS Sierra. This computer took about 44 hours 35 minutes to complete the primality test using LLR. Sam is a member of the DONTPANIC team.

For more details, please see the official announcement.

2017-08-26: Another PPS-Mega Prime!

On 24 August 2017 11:36:16 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1119*2^3422189+1

The prime is 1,030,185 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 200th overall.

The discovery was made by Jochen Beck (dh1saj) of Germany using an Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz with 8GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 1 hour 19 minutes to complete the primality test using LLR. Jochen is a member of the SETI.Germany team.

The prime was verified on 24 August 2017 20:58:29 UTC by Gerrit Slomma (roadrunner_gs) of Germany using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 6GB RAM, running Linux. This computer took about 1 hour 44 minutes to complete the primality test using LLR. Gerrit is a member of the Special: Off-Topic team.

For more details, please see the official announcement.

2017-08-23: Another PPS-Mega Prime!

On 18 August 2017 19:28:05 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1005*2^3420846+1

The prime is 1,029,781 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 199th overall.

The discovery was made by ?ukasz Piotrowski (stiven) of Poland using an Intel(R) Xeon(R) E3-1220 v3 CPU @ 3.10GHz with 4GB RAM, running Linux. This computer took about 1 hour 1 minute to complete the primality test using LLR. ?ukasz is a member of the BOINC@Poland team.

The prime was verified on 21 August 2017 06:11:37 UTC by Milan F?a?ek (RNDr.) of the Czech Republic using an Intel(R) Core(TM) i3-2100 CPU @ 3.10GHz with 4GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 2 hours 9 minutes to complete the primality test using LLR. Milan is a member of the Czech National Team.

For more details, please see the official announcement.

2017-08-23: World Record Generalized Cullen Prime!

On 21 August 2017, 14:51:43 UTC, PrimeGrid?s Generalized Cullen/Woodall Prime Search found the largest known generalized Cullen prime:

1341174*53^1341174+1

Generalized Cullen numbers are of the form: n*b^n+1. Generalized Cullen numbers that are prime are called generalized Cullen primes. For more information, please see ?Cullen prime? in The Prime Glossary.

The prime is 2,312,561 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Cullen primes and 30th overall.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) CPU @ 2.90GHz with 16GB RAM, running Linux. This computer took about 12 hours and 39 minutes to complete the primality test using multithreaded LLR. Hiroyuki is a member of the Aggie The Pew team.

The prime was verified on 22 August 2017 17:24:17 UTC by user wuzzat of Australia using an Intel(R) Xeon(R) E5-2620 v3 CPU @ 2.40GHz with 256GB RAM, running Microsoft Windows Server 2008R2. This computer took about 31 hours 41 minutes to complete the primality test using LLR. Wuzzat is a member of the BOINC@AUSTRALIA team.

For more details, please see the official announcement.

2017-08-15: Solar Eclipse Challenge Starts August 20th at 18:00 UT

It's the challenge you've been waiting for, GCW-LLR!

Running from August 20th 18:00 UTC until August 23rd 18:00 UTC.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7540

So come and join us and celebrate the Solar eclipse of August 21, 2017.

2017-08-14: And, Its Another PPS-Mega Prime!

On 10 August 2017, 18:14:53 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

975*2^3419230+1

The prime is 1,029,294 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 199th overall.

The discovery was made by Eric Eskam (Doc No) of the United States using an Intel(R) Core(TM)2 Quad Q6600 CPU @ 2.40GHz with 3GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 4 hours 47 minutes to complete the primality test using LLR. Eric is a member of the Heinlein Fans team.

The prime was verified on 10 August 2017, 18:58:22 UTC by Stephen Draycott (Stephen Draycott) of the United Kingdom using an Intel(R) Xeon(R) E5-2670v3 CPU @ 2.30GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 2 hours 2 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-08-14: Another PPS-Mega Prime!

On 9 August 2017, 00:27:22 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
999*2^3418885+1

The prime is 1,029,190 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 198th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 20 minutes to complete the primality test using LLR.

The prime was verified on 9 August 2017, 04:07:04 UTC by Eric Eskam (Doc No) of the United States using an Intel(R) Core(TM)2 Quad Q6600 CPU @ 2.40GHz with 3GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 5 hours 2 minutes to complete the primality test using LLR. Eric is a member of the Heinlein Fans team.

For more details, please see the official announcement.

2017-08-08: Another PPS-Mega Prime!

On 5 August 2017 02:19:51 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
907*2^3417890+1

The prime is 1,028,891 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 197th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-7500 CPU @ 3.40GHz with 16GB RAM, running Linux. This computer took about 1 hour 2 minutes to complete the primality test using LLR.

The prime was verified on 5 August 2017 02:48:34 UTC by Seonghwan Kim (ext2097) of South Korea using an Intel(R) Xeon(R) E3-1231 v3 CPU @ 3.40GHz with 4GB RAM, running Linux. This computer took about 17 minutes to complete the primality test using multithreaded LLR. Seonghwan is a member of the SETIKAH@KOREA team.

For more details, please see the official announcement.

2017-07-17: Yet Another GFN-131072 Mega Prime!

On 15 July 2017, 21:04:54 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46776558^131072+1

The prime is 1,005,326 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 24th for Generalized Fermat primes and 240th overall.

The discovery was made by Giles Averay-Jones (Dingo) of Australia using an AMD Radeon 7700 series GPU in an Intel(R) Core(TM) i7-4771 CPU at 3.60GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 41 minutes to probable prime (PRP) test with GeneferOCL2. Giles is a member of the BOINC@AUSTRALIA team.

The prime was verified on 15 July 2017, 22:10:39 UTC by Dirk Sellsted (Dirk Sellsted) of Canada using an Nvidia Geforce GTX 1080 Ti GPU in an AMD Ryzen 7 1800X CPU with 32GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 6 minutes to probable prime (PRP) test with GeneferOCL2.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 7 Ultimate Edition. This computer took about 2 hours 45 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-07-12: Another GFN-131072 Mega Prime!

On 10 July 2017, 08:34:34 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46736070^131072+1

The prime is 1,005,277 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 24th for Generalized Fermat primes and 240th overall.

The discovery was made by Tom Greer (tng*) of the United States using an NVidia GeForce GTX 1080 GPU in an Intel(R) Core(TM) i7-6850K CPU at 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 15 minutes to probable prime (PRP) test with GeneferOCL2. Tom is a member of the Sicituradastra. team.

The prime was verified on 11 July 2017, 04:33:58 UTC by Thomas Midle (BoSoxFan86) of the United States using an AMD Radeon R7 M270 GPU in an Intel(R) Core(TM) i7-5500U CPU @ 2.40GHz with 12GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 2 hours 7 minutes to probable prime (PRP) test with GeneferOCL2. Thomas is a member of the Gridcoin team.

The PRP was confirmed prime by an Intel(R) Xeon (R) E5-2670 CPU CPU @ 2.60GHz with 32GB RAM, running Linux. This computer took about 15 hours 20 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-07-11: GFN-131072 Mega Prime!

On 9 July 2017, 15:35:22 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46730280^131072+1

The prime is 1,005,270 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 24th for Generalized Fermat primes and 240th overall.

The discovery was made by Jochen Beck (dh1saj) of Germany using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM)2 Quad Q9550 CPU at 2.83GHz with 10GB RAM, running Microsoft Windows 7 Professional Edition. This GPU took about 13 minutes to probable prime (PRP) test with GeneferOCL2. Jochen is a member of the SETI.Germany team.

The prime was verified on 9 July 2017, 16:05:01 UTC by R

2017-07-05: GFN-262144 Mega Prime!

On 30 June 2017, 02:54:43 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

3060772^262144+1

The prime is 1,700,222 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 50th overall.

The discovery was made by Sean Humphries (No.15) of the United States using an NVIDIA GeForce GTX 1080 in an Intel(R) Xeon(R) E5-2670 CPU at 2.60GHz with 32GB RAM, running Linux. This GPU took about 16 minutes to probable prime (PRP) test with GeneferOCL3. Sean is a member of the Overclock.net team.

The prime was verified on 1 July 2017, 18:49:46 UTC by John Hall (JH30895) of the United States using an NVIDIA GeForce GTX 680 in a dual Intel(R) Xeon(R) X5680 CPU @ 3.33 GHz with 24GB RAM, running macOS Sierra. This GPU took about 52 minutes to probable prime (PRP) test with GeneferOCL5. John is a member of the Ars Technica team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 4 hours 18 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-07-02: Urgent: Enable Prime Reporting Before It's Too Late

We say it all the time, but now you can lose out if you don't have prime reporting enabled.

SGS primes are currently only on the T5K list for a few days before falling off the list. If you do not have prime reporting enabled, there may be no time to contact you before it's too late to report your prime. Rather than let the prime go unreported, we will report SGS primes under the DCer's name if you don't have prime reporting enabled. If the DCer also doesn't have prime reporting enabled, we will report the prime anonymously. The alternative is that the prime doesn't get reported at all.

For more details and discussion please see the 4888 thread in our Sophie Germain Prime Search topic.

To enable prime reporting, please go to "Your account" on the menu on the left, then select "PrimeGrid Preferences". Scroll down a bit to where it says "Primary (default) preferences:" and select "Edit PrimeGrid Preferences".

Scroll down to "Reporting primes to the Prime Pages" and click the two checkboxes for granting permission to report primes and to send you an email when a prime is found. You must enter your real name. T5K will not accept fake names or user names. Please enter your name as "given-name surname". (Note that even in cultures where the surname is normally put first, we need the given name first and the surname last.)

If for any reason you don't want us to use your name, we can report anonymously for you -- just check the permission box and enter something like "report anonymously" in the name box.

Finally, scroll down to the bottom and click on the "Update preferences" button.

2017-06-26: Another PPS-Mega Prime!

On 20 June 2017, 17:28:20 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
953*2^3405729+1

The prime is 1,025,230 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 201st overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 14 minutes to complete the primality test using LLR.

The prime was verified on 24 June 2017 06:23:26 UTC, by Jon Goral ([KWSN]John Galt 007) of the United States using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 10GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 5 hours 54 minutes to complete the primality test using LLR. Jon is a member of The Knights Who Say Ni! team.

For more details, please see the official announcement.

2017-06-14: Finally, Another PPS-Mega Prime!

On 13 June 2017, 10:46:25 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

833*2^3403765+1

The prime is 1,024,639 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 21 minutes to complete the primality test using LLR.

The prime was verified on 13 June 2017, 16:05:06 UTC by Michael Bowe (No_Name) of Germany using an Intel(R) Xeon(R) E3-1230 v5 CPU @ 3.40GHz with 32GB RAM, running Microsoft Windows Server 2012 R2 Foundation Edition. This computer took about 1 hour 24 minutes to complete the primality test using LLR. Michael is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-06-08: Birthday invitation

You're invited to PrimeGrid's Birthday Party!
Where: Sophie Germain Prime Search
When: June 12th 00:00 UTC for 24 hours

Birthday Primes are bound to be found.
You can join the festivities on this thread.

We hope to see you there and please spread the word :)

Happy Birthday PrimeGrid!

2017-06-07: Yet Another GFN-131072 Mega Prime!

On 4 June 2017, 04:02:39 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46413358^131072+1

The prime is 1,004,883 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.

The discovery was made by Sagi Iltus (sagiil) using an Intel(R) Xeon(R) E5-2673 v3 CPU at 2.40GHz with 8GB RAM, running Linux. This CPU took about 7 hours 4 minutes to probable prime (PRP) test with Genefer.

The prime was verified on 7 June 2017, 18:18:37 UTC by Dirk Broer (Dirk Broer) of the British Virgin Islands using an AMD Athlon(TM) 5350 APU with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 4 hours 1 minute to probable prime (PRP) test with GeneferOCL2. Dirk is a member of the AMD Users team.

The PRP was confirmed prime by an Intel(R) Xeon (R) E5-2670 CPU CPU @ 2.60GHz with 32GB RAM, running Linux. This computer took about 15 hours 21 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-06-01: Another GFN-131072 Mega Prime!

On 31 May 2017, 09:22:45 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46385310^131072+1

The prime is 1,004,848 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.

The discovery was made by Matt Jurach (mattozan) of the United States using an AMD Pitcairn GPU in an Intel(R) Core(TM) i7-5820K CPU at 3.30GHz with 16GB RAM, running Microsoft Windows 7 Enterprise Edition. This GPU took about 42 minutes to probable prime (PRP) test with GeneferOCL2. Matt is a member of the Aggie The Pew team.

The prime was verified on 31 May 2017, 22:53:40 UTC by Krzysztof Ostaszewski (Krzysiak_PL_GDA) of Poland using an AMD R9 Fury Series GPU in an Intel(R) Xeon(R) E5-2683 v3 CPU at 2.00GHz with 32GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 11 minutes to probable prime (PRP) test with GeneferOCL2. Krzysztof is a member of the BOINC@Poland team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 52 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-05-30: GFN-131072 Mega Prime!

On 29 May 2017, 07:16:40 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46371508^131072+1

The prime is 1,004,831 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.

The discovery was made by Mike Kinney (Mektacular) of the United States using an NVIDIA GeForce GTX 950 in an Intel(R) Xeon(R) E5-2670 CPU at 2.60GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 21 minutes to probable prime (PRP) test with GeneferOCL2. Mike is a member of the Crunching@EVGA team.

The prime was verified on 29 May 2017, 14:11:46 UTC by Matt Jurach (mattozan) of the United States using an NVIDIA GeForce GTX 460 in an Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz with 8GB RAM, running Microsoft Windows 7 Ultimate Edition. This GPU took about 36 minutes to probable prime (PRP) test with GeneferOCL2. Matt is a member of the Aggie The Pew team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 41 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-05-30: Another PPS Mega Prime!

On 27 May 2017, 18:34:13 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1167*2^3399748+1

The prime is 1,023,430 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Eric Eskam (Doc No) of the United States using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hour 17 minutes to complete the primality test using LLR. Eric is a member of the Heinlein Fans team.

The prime was verified on 27 May 2017, 20:33:53 UTC by Amy Chambers (Buckeye74) of the United States using an Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 1 hour 15 minutes to complete the primality test using LLR. Amy is a member of the Sigma Omicron Chapter of Tau Kappa Epsilon team.

For more details, please see the official announcement.

2017-05-27: PRPNet May-June Challenge

Cube Challenge 3^3=27

Please join us for a PRPNet challenge at the 27 prime search project from the 27th May till 3rd of June.
Leading edge of the search now up to 6,525,272 on both the plus and minus sides. Goal will be to get to 6.6M and hopefully find a big prime!
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2017 PRPNet May-June Challenge.

Good luck!

2017-05-24: Why Not? Another PPS-Mega Prime!

On 22 May 2017 21:53:30 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

611*2^3398273+1

The prime is 1,022,985 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 18 minutes to complete the primality test using LLR.

The prime was verified on 24 May 2017 04:17:13 UTC by Luis DeJesus (lajjr) of the United States using an Intel(R) Core(TM) i7-4510U @ 2.00GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 5 hours 10 minutes to complete the primality test using LLR. Luis is a member of the Latinos Aqui team.

For more details, please see the official announcement.

2017-05-22: Another PPS-Mega Prime!

On 29 April 2017 14:06:48 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

609*2^3392301+1

The prime is 1,021,188 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by User ?jimmy? of Belgium using an Intel(R) Core(TM) i7-4790 @ 3.60GHz with 12GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 1 hour 36 minutes to complete the primality test using LLR.

The prime was verified on 30 April 2017 11:22:53 UTC by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 14 minutes to complete the primality test using LLR.

For more information, please see the official announcement.

2017-05-14: Another PPS-Mega Prime!

On 12 May 2017, 19:12:52 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

1049*2^3395647+1

The prime is 1,022,195 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 203rd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 4GB RAM, running Microsoft Windows 7 Enterprise Edition. This computer took about 1 hour 36 minutes to complete the primality test using LLR.

The prime was verified on 14 May 2017 09:32:20 UTC, by Sven L

2017-05-11: WSS and Wieferich Searches Suspended

The PRPNet Wall-Sun-Sun and Wieferich projects have been suspended. Please click here for more information and discussion.

2017-05-05: Yet Another PPS-Mega Prime!

On 3 May 2017, 19:30:03 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

555*2^3393389+1

The prime is 1,021,515 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 203rd overall.

The discovery was made by Douglas B. McKay (KD7LRJ) of the United States using an Intel(R) Core(TM) i7-4790K CPU @ 4.00 GHz with 32GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hour 15 minutes to complete the primality test using LLR. Douglas is a member of the Aggie The Pew team.

The prime was verified on 3 May 2017 20:11:14 UTC, by John Murphy (TheDawgz) of the United States using an Intel Virtual CPU with 1GB RAM, running Linux. This computer took about 1 hour 24 minutes to complete the primality test using LLR. John is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2017-05-04: PRPNet May Challenge

Primorial May the 4th Be With You Challenge

"There is a great disturbance in the Force."
"I have felt it."
Announced is a PRPNet challenge at the Primorial prime search project from the 4th till 9th of May.
Leading edge of the search now up to 2,510,533 on both the plus and minus side. Goal will be to get to 2.6M.
Discussion and more information can be found here: 2017 PRPNet May Challenge.

May the Force be with you!

2017-05-01: Another PPS-Mega Prime!

On 28 April 2017, 04:22:38 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

805*2^3391818+1

The prime is 1,021,042 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 204th overall.

The discovery was made by Reiner Elgetz (reiner) of Germany using an AMD Ryzen 7 1700 with 16GB RAM, running Linux. This computer took about 21 minutes to complete the primality test using LLR with 8 threads. Reiner is a member of the Planet 3DNow! team.

The prime was verified on 28 April 2017 13:44:43 UTC, by William Finn (W.L.F.) of the United States using an Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz with 24GB RAM running Microsoft Windows 10 Professional Edition. This computer took about 1 hour 36 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-05-01: GFN-131072 Mega Prime!

On 26 April 2017, 17:34:00 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

46077492^131072+1

The prime is 1,004,469 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 230th overall.

The discovery was made by Jeffrey Mangio (Novanglus) of the United States using an NVIDIA GeForce GTX 1080 in an Intel(R) Core(TM) i5-4690K CPU at 3.50GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 9 minutes to probable prime (PRP) test with GeneferOCL4. Jeffrey is a member of the SETI.USA team.

The prime was verified on 27 April 2017, 13:33:00 UTC by Osamu Andou (o-ando) of Japan using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-6700 CPU at 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 13 minutes to probable prime (PRP) test with GeneferOCL4.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 29 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-04-29: New sub-project: GCW-LLR

We have opened up a new subproject, GCW-LLR. It is a CPU-only project. Task sizes are initially very small, but I expect them to grow in size fairly rapidly. There is a new set of badges for the GCW-LLR project.

Please see this thread in the GCW forum for more details and discussion.

2017-04-25: Action may be required: TRP-Sieve is now shut down.

The TRP Sieve project has come to an end, and work generation for that subproject has stopped. While there will be a few recycled tasks available for a short time, eventually they will all be gone.

If TRP-Sieve is the only PrimeGrid subproject you're running, you should select another of our subprojects to run. We suggest GCW-Sieve. It's very similar to TRP-Sieve.

Since TRP-Sieve previously was automatically assigned to new users, if you've never explicitly selected which subproject to run, there's a good chance your computer is currently configured to TRP-Sieve. Please go to the PrimeGrid preferences page to change your preferences.

For discussion and more information, please see this forum thread.

2017-04-25: Another PPS-Mega Prime!

On 23 April 2017, 22:31:40 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

663*2^3390469+1

The prime is 1,020,636 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by Rolf Henrik Nilsson (puh32) of Sweden using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 49 minutes to complete the primality test using LLR.

The prime was verified on 24 April 2017 11:04:31 UTC, by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM running Linux. This computer took about 1 hour 8 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-04-06: Celebrate Mathematics Awareness Month with PrimeGrid!

Please join PrimeGrid in celebrating Mathematics Awareness Month by participating in our "Mathematics Awareness Month Challenge", beginning Friday, April 7th, at 12:00:00 UTC. Please note that this is 6 hours earlier than our nominal challenge starting time.

This challenge is being offered on the Prime Sierpinski Project (LLR), and will run for 15 days. We're currently running a double check of older PSP work, so the PSP tasks are currently much shorter than normal.

For more information, or to discuss the challenge, please see this thread on our forums.

2017-03-23: GFN-262144 Mega Prime!

On 22 March 2017, 09:33:58 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2676404^262144+1

The prime is 1,684,945 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 52nd overall.

The discovery was made by Wolfgang Schwieger (DeleteNull) of Germany using an NVIDIA GeForce GTX 1070 in an Intel(R) Core(TM) i7-6700K CPU at 4.00GHz with 16GB RAM, running Linux. This GPU took about 16 minutes to probable prime (PRP) test with GeneferOCL4. Wolfgang is a member of the SETI.Germany team.

The prime was verified on 22 March 2017, 23:16:34 UTC by William de Thomas (wdethomas) of Puerto Rico using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-4790K CPU at 4.00GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL4. William is a member of the Puerto Rico Assisting Science team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 8 hours 40 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-03-19: GFN-131072 Mega Prime!

On 18 March 2017, 21:52:24 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

45570624^131072+1

The prime is 1,003,840 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 22nd for Generalized Fermat primes and 231st overall.

The discovery was made by Vince Splain (yank) of The United States using an NVIDIA GeForce GTX 980 in an Intel(R) Core(TM) i7-5960X CPU at 3.00GHz with 16GB RAM, running Microsoft Windows 7 Professional Edition. This GPU took about 14 minutes to probable prime (PRP) test with GeneferOCL4. Vince is a member of the US Navy team.

The prime was verified on 20 March 2017, 03:07:07 UTC by Brett Melvold (AgentQ) of Australia using an AMD R9 Fury Series GPU in an Intel(R) Core(TM) i7-5820K CPU at 3.30GHz with 32GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL4. Brett is a member of the BOINC@AUSTRALIA team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 38 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-03-15: Yet Another PPS-Mega Prime!

On 14 March 2017 14:01:17 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
621*2^3378148+1

The prime is 1,016,927 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 2 minutes to complete the primality test using LLR.

The prime was verified on 14 March 2017 14:09:41 UTC by Lars Fricke (Lars Fricke) of Germany using an Intel(R) Xeon(R) E5-2660v3 @ 2.60GHz with 128GB RAM, running Linux. This computer took about 1 hour 10 minutes to complete the primality test using LLR. Lars is a member of the Rechenkraft.net team.

For more details, please see the official announcement.

2017-03-15: Another PPS-Mega Prime!

On 14 March 2017 09:23:13 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
1093*2^3378000+1

The prime is 1,016,883 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by Andreas Rohmann (Andreas Rohmann) of Germany using an Intel(R) Core(TM) i7-4771 @ 3.50GHz with 32GB RAM, running MacOS. This computer took about 2 hours 28 minutes to complete the primality test using LLR.

The prime was verified on 14 March 2017 16:51:12 UTC by Wolfgang Schwieger (DeleteNull) of Germany using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hour 30 minutes to complete the primality test using LLR. Wolfgang is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-03-15: PRPNet March Challenge

Happy St Patrick's Equinox Challenge

Announced is a PRPNet challenge at the 121 prime search project from the 16th till 21st of March.
Work in PRPNet counts towards your PSA badge.
Leading edge of the search now up to 7,360,477 on both the plus and minus side. Goal will be to get both to 7.5M.
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=121:100:1:prpnet.primegrid.com:12001
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2017 PRPNet March Challenge.

Good luck!

2017-03-15: PPS Mega Prime!

On 12 March 2017 18:28:04 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
861*2^3377601+1

The prime is 1,016,763 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by Mike Kinney (Mektacular) of the United States using an Intel(R) Core(TM) i5-6500 @ 3.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 53 minutes to complete the primality test using LLR. Mike is a member of the Crunching@EVGA team.

The prime was verified on 12 March 2017 18:47:34 UTC by Stefan Geiger (Steve) of Austria using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 52 minutes to complete the primality test using LLR. Stefan is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2017-03-15: PPS-Mega Prime!

On 12 March 2017 18:28:04 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
861*2^3377601+1

The prime is 1,016,763 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 205th overall.

The discovery was made by Mike Kinney (Mektacular) of the United States using an Intel(R) Core(TM) i5-6500 @ 3.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 53 minutes to complete the primality test using LLR. Mike is a member of the Crunching@EVGA team.

The prime was verified on 12 March 2017 18:47:34 UTC by Stefan Geiger (Steve) of Austria using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 52 minutes to complete the primality test using LLR. Stefan is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2017-03-13: GFN-262144 Mega Prime!

On 11 March 2017, 18:07:33 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2611204^262144+1

The prime is 1,682,141 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 52nd overall.

The discovery was made by Roman Vogt (Tabaluga) of Germany using an NVIDIA GeForce GTX 580 in an Intel(R) Core(TM) i7-2700K CPU @ 3.50GHz with 8GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 46 minutes to probable prime (PRP) test with GeneferOCL4. Roman is a member of the Sicituradastra. team.

The prime was verified on 12 March 2017, 12:13:28 UTC by Markus Tervooren (mtervooren) of Germany using an AMD Ellesmere GPU in an AMD Phenom(tm) II X6 1090T with 8GB RAM, running Linux. This computer took about 29 minutes to complete the probable prime (PRP) test.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Windows 10 Professional Edition. This computer took about 7 hours 28 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-02-25: GFN-262144 Mega Prime!

On 24 February 2017, 07:16:40 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2514168^262144+1

The prime is 1,677,825 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 52nd overall.

The discovery was made by William de Thomas (wdethomas) of Puerto Rico using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-4790K CPU at 4.00GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL4. William is a member of the Puerto Rico Assisting Science team.

The prime was verified on 24 February 2017, 12:21:21 UTC by Hans-Jรผrgen Bergelt (Hans-Jรผrgen Bergelt) of Germany using an NVIDIA GeForce GTX 690 in an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 8GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 37 minutes to probable prime (PRP) test with GeneferOCL4. Hans-Jรผrgen is a member of the SETI.Germany team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 8 hours 7 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-02-25: TRP-Sieve ending soon (again!)

It took longer than we anticipated, but we're moving forward now with our plans to complete the TRP-Sieve. Our rough estimate is that it will take about a month or two to reach optimal sieving depth.

I suspect most folks already did their "final badge hunting" when we first announced this back in August and September, but if you want to push for that next TRP-Sieve badge, now is the time to do it!

More details and discussion can be found in this forum thread.

2017-02-23: GFN-131072 Mega Prime!

On 23 February 2017, 02:20:15 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
45315256^131072+1

The prime is 1,003,520 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 20th for Generalized Fermat primes and 223rd overall.

The discovery was made by William Donovan (Williamd007) of the United States using an NVIDIA GeForce GTX 1070 in an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 9 minutes to probable prime (PRP) test with GeneferOCL4. William is a member of The Knights Who Say Ni! team.

The prime was verified on 23 February 2017, 06:00:13 UTC by Andrea Tosatto (Andrea Tosatto - Italy) of Italy using an Intel(R) Core(TM)2 Duo CPU @ 3.00GHz with 2GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 9 hours 17 minutes to complete the probable prime (PRP) test.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Windows 10 Professional Edition. This computer took about 1 hour 17 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-02-22: PPS-Mega Prime, Wednesday Edition

On 21 February 2017 08:08:07 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
839*2^3369383+1

The prime is 1,014,289 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Robert Lacroix (composite) of Canada using an Intel(R) Core(TM) i7-5820K @ 3.30GHz with 16GB RAM, running Linux. This computer took about 1 hour 20 minutes to complete the primality test using LLR.

The prime was verified on 21 February 2017, 08:16:49 UTC by Eric Ueda (SlangNRox) of Germany using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hours 40 minutes to complete the primality test using LLR. Eric is a member of the TeAm AnandTech team.

For more details, please see the official announcement.

2017-02-21: PPS-Mega Prime, Tuesday Edition

On 20 February 2017 14:39:06 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
677*2^3369115+1

The prime is 1,014,208 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Wolfgang Schmidt (Artist) of Germany using an Intel(R) Core(TM) i7-4770 @ 3.40GHz with 16GB RAM, running Linux. This computer took about 54 minutes to complete the primality test using LLR. Wolfgang is a member of the Special: Off-Topic team.

The prime was verified on 21 February 2017, 15:15:01 UTC by Hans-Jรผrgen Bergelt (Hans-Jรผrgen Bergelt) of Germany using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 2 hours 26 minutes to complete the primality test using LLR. Hans-Jรผrgen is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-02-20: PPS-Mega Prime, Saturday Edition, Part Two

On 18 February 2017 11:07:35 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
715*2^3368210+1

The prime is 1,013,936 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Daniel Fru?y?ski (Daniel) of Poland using an Intel(R) Xeon(R) CPU E5-2670 @ 2.60GHz with 32GB RAM, running Linux. This computer took about 1 hour 54 minutes to complete the primality test using LLR. Daniel is a member of the BOINC@Poland team.

The prime was verified on 18 February 2017, 23:47:33 UTC by Mark Dodrill (mdodrill) of the United States using an Intel(R) Core(TM) i7-6700K CPU @ 3.40GHz with 32GB RAM, running Microsoft Windows 10. This computer took about 1 hour 38 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-02-20: PPS-Mega Prime, Saturday Edition, Part One

On 18 February 2017 06:57:35 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
617*2^3368119+1

The prime is 1,013,908 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Kimmo Koski (Cinclus) of Finland using an Intel(R) Core(TM) i7-4790 @ 3.60GHz with 24GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 1 hour 42 minutes to complete the primality test using LLR. Kimmo is a member of the Aggie The Pew team.

The prime was verified on 18 February 2017, 09:31:18 UTC by Alen Kecic (Freezing) of Germany using an Intel(R) Core(TM) i5-4219M CPU @ 2.60GHz with 8GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 56 minutes to complete the primality test using LLR. Alen is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-02-20: PPS-Mega Prime, Friday Edition

On 17 February 2017 00:26:30 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
777*2^3367372+1

The prime is 1,013,683 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.

The discovery was made by Lars Fricke (Lars Fricke) of Germany using an Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz with 64GB RAM, running Linux. This computer took about 1 hour 34 minutes to complete the primality test using LLR.

The prime was verified on 17 February 2017, 17:55:08 UTC by Hans-Jรผrgen Bergelt (Hans-Jรผrgen Bergelt) of Germany using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 7 Home Premium Edition. This computer took about 1 hour 55 minutes to complete the primality test using LLR. Hans-Jรผrgen is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-02-10: Yes, Its Another PPS-Mega Prime!

On 9 February 2017, 17:56:42 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
533*2^3362857+1

The prime is 1,012,324 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 203rd overall.

The discovery was made by Hans-Jรผrgen Bergelt (Hans-Jรผrgen Bergelt) of Germany using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 8GB RAM, running Microsoft Windows 7 Ultimate Edition. This computer took about 1 hour 18 minutes to complete the primality test using LLR. Hans-Jรผrgen is a member of the SETI.Germany team.

The prime was verified on 10 February 2017, 00:06:03 UTC by Steve King (steveking) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 20GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hour 20 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-02-10: Another PPS Mega Prime!

On 9 February 2017, 08:57:25 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
619*2^3362814+1

The prime is 1,012,311 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 203rd overall.

The discovery was made by Daniel Fru?y?ski (Daniel) of Poland using an Intel(R) Xeon(R) CPU E5-2670 @ 2.60GHz with 32GB RAM, running Linux. This computer took about 1 hour 49 minutes to complete the primality test using LLR. Daniel is a member of the BOINC@Poland team.

The prime was verified on 9 February 2017, 09:18:53 UTC by Alen Kecic (Freezing) of Germany using an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 56 minutes to complete the primality test using LLR. Alen is a member of the SETI.Germany team.

For more details, please see the official announcement.

2017-02-08: Better Late Than Never: 2017 Tour de Primes!

PrimeGrid's annual Tour de Primes is underway!

Unlike other challenges, there's no trophy for participation. This challenge is all about finding prime numbers.

As with last year, there will also be a red jersey -- which will be awarded to whomever finds the largest prime number during the month of February.

And, of course, we'll be awarding the green, yellow, and polk-a-dot jerseys as in previous years.

For more information, please see Tour de Primes 2017.

Good luck everyone!

2017-02-01: GFN-131072 Mega Prime!

On 1 February 2017, 02:24:46 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

44919410^131072+1

The prime is 1,003,020 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 19th for Generalized Fermat primes and 215th overall.

The discovery was made by Vince Splain (yank) of The United States using an NVIDIA GeForce GTX 980 in an Intel(R) Core(TM) i7-5960X CPU at 3.00GHz with 16GB RAM, running Microsoft Windows 7 Professional. This GPU took about 14 minutes to probable prime (PRP) test with GeneferOCL4. Vince is a member of the US Navy team.

The prime was verified on 3 February 2017, 21:17:17 UTC by William Donovan (Williamd007) of the United States using an NVIDIA GTX 960 on an AMD FX(tm)-9590 CPU with 16GB RAM, running Microsoft Windows 10 Core Edition. This GPU took about 22 minutes to PRP test with GeneferOCL4. William is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 5 hours 17 minutes to complete the primality test using LLR.

For more information, please see the official announcement.

2017-01-23: Another PPS Mega Prime!

On 19 January 2017, 22:43:32 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

1183*2^3353058+1

The prime is 1,009,375 digits long and will enter Chris Caldwell's ?The Largest Known Primes Database? ranked 202nd overall.

The discovery was made by Michele T. Mazzucato (nillium) of Italy using an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 8GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 2 hours 26 minutes to complete the primality test using LLR.

The prime was verified on 20 January 2017, 00:27:58 UTC by Akinori Kanno (teagin) of Japan using an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 2 hours 49 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2017-01-20: ALERT: prothsearch.net is now prothsearch.com

The prothsearch.net domain has been stolen by a cybersquatter. The real website is being rebuilt at http://prothsearch.com. The squatter is using some content from the old website to make the new, fake website look "real". This is clearly an act of deception. It's unclear whether the squatter merely wants to use the site as clickbait for ads or wants to do something more nefarious such as distributing maleware. Either way, please avoid the old website, and please pass this information along to others in the prime search community. Thank you!

2017-01-17: PPS Mega Prime!

On 16 January 2017, 04:34:40 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

543*2^3351686+1

The prime is 1,008,961 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 201st overall.

The discovery was made by Simon Rawles (rawles) of the United Kingdom using an Intel(R) Core(TM) i7-5960X CPU @ 3.00GHz with 32GB RAM, running Linux. This computer took about 56 minutes to complete the primality test using LLR.

The prime was verified on 16 January 2017, 05:06:22 UTC by Ed Goforth (BlisteringSheep) of Saint Kitts and Nevis using an Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz with 64GB RAM, running Microsoft Windows Server 2012 R2. This computer took about 1 hour 35 minutes to complete the primality test using LLR. Ed is a member of the Christians team.

For more details, please see the official announcement.

2017-01-02: Join us for some Newtonian fun!

Beginning on Tuesday, January 3rd, PrimeGrid will be celebrating Isaac Newton's Birthday with our first challenge of the new year.

Please join us by running the GCW-Sieve project during the 10-day challenge, which runs from January 3rd, 18:00:00 UTC until January 13th, 18:00:00 UTC. This challenge has a specific purpose: we have a lot of sieving to do before we can open up GCW-LLR on the BOINC server.

More information and discussion can be found in the official challenge forum discussion.

So come and join us in honoring Sir Isaac Newton's birthday!

2016-12-14: Winter Solstice Challenge starts Dec 18th, 10:44 UTC

The end of the year is drawing closer and this is traditionally marked with the winter solstice challenge here at PrimeGrid. As in previous years we would like to invite everyone to join us in this celebration of tidings of comfort and joy by sieving away for the Proth Prime Search. The challenge will start on Dec 18 10:44 UTC and last for 72 hours.

For more information, cheery banter and general merrymaking please join us on the discussion board.

We hope to see you there and please do spread the word :)

2016-12-14: GFN-131072 Mega Prime!

On 11 December 2016, 02:52:40 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

44438760^131072+1

The prime is 1,002,408 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 19th for Generalized Fermat primes and 198th overall.

The discovery was made by Hรฅkan Lind (sangis43) of Sweden using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i7-6800k CPU with 16GB RAM, running Microsoft Windows 10 Professional. This GPU took about 22 minutes to probable prime (PRP) test with GeneferOCL4. Hรฅkan is a member of the Sicituradastra. team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM, running Windows 7 Ultimate. This computer took about 8 hours 58 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-12-13: Another PPS Mega Prime!

On 12 December 2016, 08:33:42 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
733*2^3340464+1

The prime is 1,005,583 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 191st overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 14 minutes to complete the primality test using LLR.

The prime was verified on 13 December 2016, 05:33:05 UTC by Rafal Foryszewski (4ys) of Poland using an Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz with 2GB RAM, running Microsoft Windows XP Professional. This computer took about 5 Hours 56 minutes to complete the primality test using LLR. Rafal is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2016-12-12: AP26 Found!

On 11 December 2016, 20:06:09 UTC, PrimeGrid?s AP27 Search (Arithmetic Progression of 27 primes) found the progression of 26 primes:

142099325379199423+16549135*23#*n for n=0..25

The discovery was made by Koichi Soraku (JG4KEZ(Koichi Soraku)) of Japan using a NVIDIA GTX 1070 on an Intel(R) Core(TM) i7-5775C @ 3.30GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 27 minutes to process the task (each task tests 100 progression differences of 10 shifts each). Koichi is a member of the BOINC@MIXI team.

The progression was verified on 12 December 2016 10:44:25 UTC, by Dirk Kraemer (DoctorNow) of Germany using an NVIDIA GTX 760 on an AMD Phenom(tm) II X6 CPU running Microsoft Windows Vista. This computer took about 2 hours 22 minutes to process the task. Dirk is a member of the BOINC Confederation.

The AP26 will be listed in Jens Kruse Andersen's Primes in Arithmetic Progression Records page under the section(s):

All known AP24 to AP26

For all APs found 23 and greater, please see PrimeGrid's AP26 Statistics.

For more details, please see the official announcement.

2016-12-05: Another PPS Mega Prime!

On 3 December 2016, 16:11:01 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
651*2^3337101+1

The prime is 1,004,571 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 192nd overall.

The discovery was made by Konstantin Stanko (Pollux) of the Czech Republic using an Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 7 Professional. This computer took about 1 hour 8 minutes to complete the primality test using LLR. Konstantin is a member of the Czech National Team.

The prime was verified on 3 December 2016, 16:24:31 UTC by Albert Symula (Albercik) of Poland using an Intel(R) Core(TM) i5-6600 @ 3.30GHz with 8GB RAM, running Microsoft Windows 10 Professional. This computer took about 57 minutes to complete the primality test using LLR. Albert is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2016-12-05: PRPNet December Challenge

Long Nights Moon Challenge

A one week challenge on the Wieferich prime search is being held during the month of December to celebrate the Supermoon on the 14th. This full moon was known by early Native American tribes as the Long Nights Moon because it occurs near the winter solstice?the night with the least amount of daylight. Challenge will start on 9th of December at 12:00 UTC.

We're currently at 5.59e17. Goal will be to get to 6.0e17. Work in this sub-project counts towards your PSA badge.
More about Wieferich prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=WIEFERICH:100:1:prpnet.primegrid.com:13000
Discussion and more information can be found here: 2016 PRPNet December Challenge.

Good luck!

2016-11-30: PPS Mega Prime, 50th Mega Prime of the Year!

On 29 November 2016, 16:00:42 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
849*2^3335669+1

The prime is 1,004,140 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 193rd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 12 minutes to complete the primality test using LLR.

The prime was verified on 29 November 2016, 18:54:26 UTC by Ed Goforth (BlisteringSheep) of Saint Kitts and Nevis using an Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz with 48GB RAM, running Linux. This computer took about 1 hour 36 minutes to complete the primality test using LLR. Ed is a member of the Christians team.

For more details, please see the official announcement.

2016-11-29: GFN-131072 Mega Prime!

On 26 November 2016, 05:43:10 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

44330870^131072+1

The prime is 1,002,270 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 19th for Generalized Fermat primes and 196th overall.

The discovery was made by Eric Eskam (Doc No) of the United States using an NVIDIA GeForce GTX 580 in an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM, running Microsoft Windows 10 Professional. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL4. Eric is a member of the Heinlein Fans team.

The was verified on 29 November 2016, 00:17:19 UTC by Brent Schneider (KWSN-SpongeBob SquarePants) of Nepal using an NVIDIA Quadro 4000 in an Intel(R) Xeon(R) W3960 CPU @ 3.47GHz with 12GB RAM, running Microsoft Windows 10 Enterprise. This GPU took about 1 hour 4 minutes to probable prime (PRP) test with GeneferOCL4. Brent is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 12GB RAM, running Windows 7 Professional. This computer took about 7 hours 10 minutes to complete the primality test using LLR.

For more details please see the official announcement.

2016-11-27: Another PPS Mega Prime!

On 27 November 2016, 04:28:15 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:
611*2^3334875+1

The prime is 1,003,901 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 193rd overall.

The discovery was made by John S. Chambers (Johnny Rotten) of the United States using an Intel(R) Core(TM) i7-5930K CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 7 Professional. This computer took about 45 minutes to complete the primality test using LLR. John is a member of the SETI.USA team.

The prime was verified on 27 November 2016 04:44:08 UTC, by John Murphy (TheDawgz) of the United States using an GenuineIntel Virtual CPU with 746MB RAM running Linux. This computer took about 53 minutes to complete the primality test using LLR. John is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2016-11-27: GFN-262144 Mega Prime!

On 24 November 2016, 03:05:38 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

2042774^262144+1

The prime is 1,654,187 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 47th overall.

The discovery was made by Tsuyoshi Ohsugi (motsu) of Japan using an NVIDIA GeForce GTX 750 Ti in an AMD Phenom(tm) II X6 1065T CPU with 12GB RAM, running Microsoft Windows 10 Professional. This GPU took about 1 hour 19 minutes to probable prime (PRP) test with GeneferOCL3. Tsuyoshi is a member of the Gridcoin team.

The prime was verified on 24 November 2016, 08:03:02 UTC by Michael Mamanakis (Michael Mamanakis) of the United States using an NVIDIA GeForce GTX 1080 in an Intel(R) Xeon(R) CPU E5-1603 @ 2.80GHz with 32GB RAM, running Microsoft Windows 7 Enterprise Edition. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL4.

The PRP was confirmed prime by an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 12GB RAM, running Windows 7 Professional. This computer took about 20 hours 36 minutes to complete the primality test using LLR.

For more information, please see the official announcement.

2016-11-15: Wallis is Born Challenge Starts November 18th at 18:00 UTC

Please join us for the Wallis is Born Challenge, running for 5 days from November 18th 18:00:00 UTC until November 23rd 18:00:00 UTC. This challenge is running the AP27 app only.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7084

2016-11-14: Another PPS Mega Prime!

On 12 November 2016, 17:02:17 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

673*2^3330436+1

The prime is 1,002,564 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 193rd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.50GHz with 8GB RAM, running Linux. This computer took about 1 hour 12 minutes to complete the primality test using LLR.

The prime was verified on 12 November 2016, 17:23:33 UTC by John S. Chambers (Johnny Rotten) of the United States using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 1 hour 23 minutes to complete the primality test using LLR. John is a member of the SETI.USA team.

For more details, please see the official announcement.

2016-11-09: World Record Colbert Number discovered!

On 31 October 2016, 22:13:54 UTC, PrimeGrid?s Seventeen or Bust subproject found the Mega Prime:

10223*2^31172165+1

The prime is 9,383,761 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 7th overall.

This is the largest prime found attempting to solve the Sierpinski Problem and eliminates k=10223 as a possible Sierpinski number. It is also the largest known Proth prime, the largest known Colbert number, and the largest prime PrimeGrid has discovered. Among the 10 largest known prime numbers, it is the only prime that is not a Mersenne number, and the only known non-Mersenne prime over 4 million digits.

Until the Seventeen or Bust project shut down earlier in the year, this search was a collaboration between PrimeGrid and Seventeen or Bust. This discovery would not have been possible without all the work done over the years by Seventeen or Bust.

The discovery was made by Szabolcs Peter (SyP) of Hungary using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 12GB RAM, running Windows 10 Enterprise Edition. This computer took about 8 days, 22 hours, 34 minutes to complete the primality test using LLR.

Information regarding double checking will be announced at a later date.

For more details, please see the official announcement.

2016-11-05: Yes, its another PPS Mega Prime!

On 4 November 2016, 06:03:37 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

655*2^3327518+1

The prime is 1,001,686 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 196th overall.

The discovery was made by Paul Mazumdar (pm107) of the United Kingdom using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Windows 10 Education Edition. This computer took about 1 hour 5 minutes to complete the primality test using LLR. Paul is a member of the University of Cambridge team.

The prime was verified on 4 November 2016, 14:34:01 UTC by Toshitaka Kumagai (Toshitaka Kumagai) of Japan using an Intel(R) Xeon(R) CPU E5-2643 @ 3.30GHz with 256GB RAM, running Windows 10 Core Edition. This computer took about 1 hour 22 Minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-11-05: Another PPS Mega Prime!

On 3 November 2016, 17:52:13 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

659*2^3327371+1

The prime is 1,001,642 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 196th overall.

The discovery was made by Dejana Ristic (Dejana Ristic) of Germany using an Intel(R) Xeon(R) CPU E3-1245 v3 @ 3.40GHz with 8GB RAM, running Windows 7 Enterprise Edition. This computer took about 1 hour 1 minute to complete the primality test using LLR. Dejana is a member of the Rechenkraft.net team.

The prime was verified on 4 November 2016, 09:03:57 UTC by Steve King (steveking) of the United States using an Intel(R) Core(TM) i3-4010U CPU @ 1.70GHz with 12GB RAM, running Windows 10 Core Edition. This computer took about 4 hours to complete the primality test using LLR.

For more details, please see the official announcement.

2016-11-04: AP26 Found!

On 3 November 2016, 23:35:42 UTC, PrimeGrid?s AP27 Search (Arithmetic Progression of 27 primes) found the progression of 26 primes:

149836681069944461+7725290*23#*n for n=0..25

The discovery was made by Takeshi Nakamura (kurogane-t) of Japan using a NVIDIA GTX 1070 on an Intel(R) Xeon(R) E5-2667 v3 @ 3.20GHz with 16GB RAM, running Windows 10 Core x64 Edition. This computer took about 30 minutes to process the task (each task tests 100 progression differences of 10 shifts each). Takeshi is a member of the BOINC@MIXI team.

The progression was verified on 4 November 2016 03:37:51 UTC, by James Nobis (quel) of the United States using an AMD Tahiti GPU on an AMD Opteron(tm) 3648 CPU running Linux. This computer took about 1 hour 21 minutes to process the task. James is a member of the Sicituradastra. team.

The AP26 will be listed in Jens Kruse Andersen's Primes in Arithmetic Progression Records page under the section(s):

? All known AP24 to AP26

For all APs found 23 and greater, please see PrimeGrid's AP26 Statistics.

For more details, please see the official announcement.

2016-11-03: PPS Mega Prime!

On 2 November 2016, 16:08:03 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

821*2^3327003+1

The prime is 1,001,531 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 196th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.50GHz with 8GB RAM, running Linux. This computer took about 1 hour 1 minute to complete the primality test using LLR.

The prime was verified on 2 November 2016, 17:04:43 UTC by Chris Hoefliger ({CurlY BracketS}) of Switzerland using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 55 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-11-02: PSP Double Check

Since the demise of the original Prime Sierpinski Project (PSP) two years ago, PrimeGrid has been continuing its own work on PSP. The time has come to double check all of the PSP tasks done external to PrimeGrid. All of our own PSP tasks are already double checked.

The double check tasks are a lot smaller than the normal PSP tasks, but there's a lot of work to be done. If you have some spare computing power and would like to contribute, you may do so by selecting "Prime Sierpinski Project LLR (PSP)' on the PrimeGrid preferences page. This is a CPU-only project.

More details and discussion can be found in this thread: http://www.primegrid.com/forum_thread.php?id=7093

2016-10-31: Another PPS Mega Prime!

On 30 October 2016, 07:20:52 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

555*2^3325925+1

The prime is 1,001,206 digits long and will enter Chris Caldwell's ?The Largest Known Primes Database? ranked 196th overall.

The discovery was made by Alexander Falk (Alexander Falk) of the United States using an Intel(R) Core(TM) i7-4690HQ CPU @ 2.60GHz with 16GB RAM, running Windows 10 Professional. This computer took about 4 hours 12 minutes to complete the primality test using LLR. Alexander is a member of The Knights Who Say Ni! team.

The prime was verified on 30 October 2016 16:18:08 UTC, by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM running Linux. This computer took about 1 hour 6 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-10-30: PRPNet November Challenge

Srinivasa Ramanujan Challenge

Announced is a PRPNet challenge at the FPS prime search project from the 3rd till 10th of November.
We remember and celebrate Srinivasa Ramanujan, an Indian mathematician and autodidact, who made extraordinary contributions to mathematical analysis, number theory, infinite series, and continued fractions.
More about factorial prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=FPS:100:1:prpnet.primegrid.com:12002

Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2016 PRPNet November Challenge

Good luck!

2016-10-25: PPS Mega Prime!

On 24 October 2016, 17:17:12 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

791*2^3323995+1

The prime is 1,000,626 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 197th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 8 minutes to complete the primality test using LLR.

The prime was verified on 26 October 2016 10:21:20 UTC, by Christoph Wolf ([CSF] Christoph Wolf) of Germany using an Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz with 8GB RAM running Windows 10 Professional. This computer took about 1 hour 11 minutes to complete the primality test using LLR. Christoph is a member of the CRUNCHERS SANS FRONTIERES team.

For more details, please see the official announcement.

2016-10-22: New BOINC Sub-Project: GCW Sieve

We have opened Generalized Cullen Woodall sieve in BOINC to do new sieving work for the upcoming GCW move from PRPNet to BOINC in early 2017. The sieve for GCW was previously a manual effort. The sieve comes with an all new badge and user statistics.

We're searching for the first known Generalized Cullen prime in each of 14 bases. Once a Prime is found work on that Base will cease. Sieving makes the up and coming LLR work more efficient by removing candidates that have factors and so can't be Prime.

For more information, or to discuss the GCW Sieve, please see this forum thread.

2016-10-22: Another PPS Mega Prime!

On 21 October 2016, 18:12:50 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

597*2^3322871+1

The prime is 1,000,287 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 197th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 11 minutes to complete the primality test using LLR.

The prime was verified on 22 October 2016 00:51:34 UTC, by Lucas Brown (LucasBrown) of the United States using an Intel(R) Core(TM) i7-6700K CPU @ 4GHz with 64GB RAM running Linux. This computer took about 46 minutes to complete the primality test using LLR. Lucas is a member of the XKCD team.

For more details, please see the official announcement.

2016-10-15: Another GFN-131072 Mega Prime!

On 14 October 2016, 19:17:01 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

44085096^131072+1

The prime is 1,001,953 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 18th for Generalized Fermat primes and 193rd overall.

The discovery was made by Alejandro V. Mena (Alejandro V. Mena) of Mexico using an NVIDIA Tesla K40c in an Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz with 56GB RAM, running Microsoft Windows 7 Professional. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL4. Alejandro is a member of the MENA_COMP_DIE_FI_UNAM team.

The prime was verified on 15 October 2016, 10:27:16 UTC by Michael Mamanakis (Michael Mamanakis) of the United States using an NVIDIA GeForce GTX 1080 in an Intel(R) Xeon(R) CPU E5-1607 v2 @ 3.00GHz with 32GB RAM, running Microsoft Windows 10 Enterprise. This GPU took about 10 minutes to probable prime (PRP) test with GeneferOCL4.

The PRP was confirmed prime by an Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz with 8GB RAM, running Windows 7 Professional. This computer took about 9 hours 14 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-10-11: PRPNet October Challenge

Prime Hunters Moon Challenge

A three day challenge on the Wieferich prime search is being held during the month of October to celebrate the Supermoon on the 16th. This full moon was known by early Native American tribes as the Full Hunters Moon because at this time of year the leaves are falling and the game is fat and ready to hunt. Challenge will start on 14th of October at 12:00 UTC.

We're currently at 5.2e17. Goal will be to get to 5.5e17. Work in this sub-project counts towards your PSA badge.
More about Wieferich prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=WIEFERICH:100:1:prpnet.primegrid.com:13000
Discussion and more information can be found here: 2016 PRPNet October Challenge.

Good luck!

2016-10-10: GFN-131072 Mega Prime!

On 5 October 2016, 19:10:08 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

44049878^131072+1

The prime is 1,001,908 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 18th for Generalized Fermat primes and 191st overall.

The discovery was made by Alexander Falk (Alexander Falk) of the United States using an NVIDIA GeForce GTX 970 in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional. This GPU took about 14 minutes to probable prime (PRP) test with GeneferOCL4. Alexander is a member of The Knights Who Say Ni! team.

The PRP was confirmed prime by an Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz with 8GB RAM, running Windows 7 Professional. This computer took about 9 hours 33 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-10-09: PRPNet GCW Mega Prime!

On 8 October 2016, 21:01:14 UTC, PrimeGrid?s PRPNet found the largest known generalized Cullen prime:

682156*79^682156+1

The prime is 1,294,484 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for generalized Generalized Cullen and Generalized Cullen-Woodall primes and 83rd overall.

The discovery was made by Franz-Xaver Harvanek (XAVER) of Austria using an Intel(R) Core(TM) i7-5960X CPU @ 3.00GHz with 32GB RAM, running Microsoft Windows 7 Ultimate. This computer took 3 hours and 44 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-10-08: Its another PPS Mega Prime!

On 8 October 2016, 05:09:38 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

415*2^3559614+1

The prime is 1,071,554 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 134th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 26 minutes to complete the primality test using LLR.

The prime was verified on 8 October 2016, 06:43:05 UTC by Alexander Falk (Alexander Falk) of the United States using an Intel(R) Xeon(TM) X5680 CPU @ 3.33GHz with 8GB RAM, running Linux. This computer took about 2 hours 57 minutes to complete the primality test using LLR. Alexander is a member of The Knights Who Say Ni! team.

For more details, please see the official announcement.

2016-10-01: Could it be? Yes, its another PPS Mega Prime!

On 30 September 2016, 09:27:42 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

465*2^3536871+1

The prime is 1,064,707 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 138th overall.

The discovery was made by Kenneth Biscop (Kenneth) of Belgium using an Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz with 7GB RAM, running Windows 8.1. This computer took about 1 hour 33 minutes to complete the primality test using LLR. Kenneth is a member of the VUB/ULB team.

The prime was verified on 30 September 2016 09:30:54 UTC, by Els Floren (Kurt Janssens) of Belgium using an Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz with 16GB RAM running Windows 8.1. This computer took about 1 hour 44 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-09-30: TRP Sieve tasks to increase in size

We expect to increase the sieve of the TRP-Sieve tasks by a factor of five sometime after 18:00 on Monday, October 3rd.

More information and discussion can be found in this forum thread: http://www.primegrid.com/forum_thread.php?id=7040

2016-09-29: Another PPS Mega Prime!

On 28 September 2016, 12:23:48 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

447*2^3533656+1

The prime is 1,063,740 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 138th overall.

The discovery was made by Stefan Geiger (Steve) of Austria using an Intel(R) Core(TM) i7-6700K CPU @ 4GHz with 16GB RAM, running Windows 10. This computer took about 42 minutes to complete the primality test using LLR. Stefan is a member of the Aggie The Pew team.

The prime was verified on 29 September 2016 06:53:13 UTC, by Eric Eskam (Doc No) of the United States using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM running Windows 10. This computer took about 1 hour 21 minutes to complete the primality test using LLR. Eric is a member of the Heinlein Fans team.

For more details, please see the official announcement.

2016-09-27: World Space Week Kickoff Challenge starts October 3rd, 18:00 UTC

Get ready for Launch! The World Space Week Kickoff Challenge is celebrating space with a 1 day challenge on the Sophie Germain Prime Search (LLR), starting 3rd October at 18:00 UTC.
It'll be a blast. Make sure you do a full system check before lift off.

For more information, questions and answers join us on the forums.

2016-09-20: The Hunt for AP27

PrimeGrid has begun searching for an AP27 (arithmetic progression of primes of 27 terms). Six years ago, we found the first known AP26. Help us search for an AP27!

Details and discussions can be found on the forums.

2016-09-20: World Record Twin Primes Found!

On 14 September 2016 04:24:46 UTC, PrimeGrid?s Sophie Germain Prime Search found World Record twin primes:

2996863034895*2^1290000ยฑ1

The twin primes are 388,342 digits long, eclipsing the previous record of 200,700 digits. They will enter Chris Caldwell's The Largest Known Primes Database ranked 1st for twins, and each entered individually ranked 4180th overall.

The discovery was made by Tom Greer (tng*) of the United States using an Intel(R) Xeon(R) CPU E5-2623 v3 @ 3GHz with 32 GB RAM running Windows 10 Professional. This computer, using LLR, took approximately 23 minutes to complete the primality tests of both primes. Tom is a member of the Sicituradastra. team.

The prime was verified on 15 September 2016 01:32:51 UTC, by Don Palmer (Don Palmer) of Canada using an Intel(R) Core(TM)2 Duo CPU E7600 @ 3.06GHz with 4 GB RAM running OS X 10.11.6. This computer, using LLR, took approximately 1 hour 37 minutes to complete the primality tests of both primes. Don is a member of the Team Canada team.

For more details, please see the official announcement.

2016-09-12: PRPNet September Challenge

Libra Equinox Challenge

Announced is a PRPNet challenge at the 27 prime search project from the 20th till 27th of September.
Leading edge of the search now up to 6,062,752 on both the plus and minus sides. Goal will be to get to 6.3M.
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.
To take part, you have to activate the following lines in prpclient.ini:
server=27:100:1:prpnet.primegrid.com:12006
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2016 PRPNet September Challenge.

Good luck!

2016-09-12: Double checking is now required for all tasks

PrimeGrid has turned on double checking for the SGS-LLR, PPSE-LLR, and PPS-LLR sub-projects. All of our other projects already had double checking enabled.

More details and discussion can be found here: http://www.primegrid.com/forum_thread.php?id=7007

2016-09-08: Another PPS Mega Prime!

On 5 September 2016, 02:15:19 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

495*2^3484656+1

The prime is 1,048,989 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 152nd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 8 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-09-07: Yes, Its Another PPS Mega Prime!

On 29 August 2016, 10:26:22 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

491*2^3473837+1

The prime is 1,045,732 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 154th overall.

The discovery was made by Stephen Norton (spnorton) of the United States using an Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 7 Professional x64 Edition. This computer took about 55 minutes to complete the primality test using LLR. Stephen is a member of the Alien Prime Cult team.

For more details, please see the official announcement.

2016-08-30: Summer Paralympics Challenge Starts September 2nd at 18:00 UT

Please join us for the Summer Paralympics Challenge, running from September 2nd 18:00:00 UTC until September 7th 18:00:00 UTC. This challenge is running the ESP-LLR app only.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=6958

2016-08-25: Another PPS Mega Prime!

On 23 August 2016, 01:58:59 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

453*2^3461688+1

The prime is 1,042,075 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 153rd overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 11 minutes to complete the primality test using LLR.

The prime was verified on 23 August 2016, 11:32:10 UTC by Franz-Xaver Harvanek (XAVER) of Austria using an Intel(R) Core(TM) i7-5960X CPU @ 3.00GHz with 32GB RAM, running Microsoft Windows 7 Ultimate. This computer took about 1 hour 17 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-08-25: SR5 Mega Prime!

On 20 August 2016, 16:21:09 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=180062 by finding the mega prime:

180062*5^2249192-1

The prime is 1,572,123 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 48th overall. This is the largest known base 5 mega prime. 74 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Stefan Larsson (288larsson) of Sweden using an Intel(R) Core(TM) i7-5775C CPU @ 3.30GHz with 8GB RAM running Linux. This computer took about 14 hours 3 minutes to complete the primality test using LLR. Stefan is a member of the Sicituradastra. team.

For more details, please see the official announcement.

2016-08-16: GFN-262144 Mega Prime!

On 10 August 2016, 19:21:20 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1828858^262144+1

The prime is 1,641,593 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 43rd overall.

The discovery was made by Brook Harste (brinktastee) of the United States using an NVIDIA GeForce GTX 980 Ti in an Intel(R) Core(TM) i7-3820 CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional. This GPU took about 17 minutes to probable prime (PRP) test with GeneferOCL4. Brook is a member of the Aggie The Pew team.

The prime was verified on 10 August 2016, 21:06:33 UTC by Frank Matillek (boss) of Germany using an NVIDIA GeForce GTX 660 Ti in an Intel(R) Core(TM)2 Quad CPU Q9400@ 2.66GHz with 4GB RAM, running Microsoft Windows 10 Professional. This GPU took about 39 minutes to probable prime (PRP) test with GeneferOCL4. Frank is a member of the SETI.Germany team.

For more details, please see the official announcement.

2016-08-16: Yet Another PPS Mega Prime!

On 25 July 2016, 05:31:32 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

479*2^3411975+1

The prime is 1,027,110 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 156th overall.

The discovery was made by Matt Jurach (mattozan) of the United States using an Intel(R) Core(TM) i7-5820k CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 7 Enterprise. This computer took about 48 minutes to complete the primality test using LLR. Matt is a member of the Aggie The Pew team.

The prime was verified on 25 July 2016, 06:24:44 UTC by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 21 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-08-07: Maintenance completed

I have completed the database optimizations that required short periods of server downtime. It is therefore once again safe to reduce your cache sizes back to 0 if you so desire.

We normally recommend running with 0 cache because it makes you more likely to be the discoverer of a prime rather than the double checker.

2016-08-06: PRPNet August Challenge

Primorial Perseids Meteor Shower Challenge

Announced is a PRPNet challenge at the Primorial prime search project from the 8th until the 15th of August.
Leading edge of the search now up to 2,204,039 on both the plus and minus side. Goal will be to get to 2.3M.
More about the Primorial prime search can be found here. News and infos about the PRPNet client can be found here.
To take part, you have to activate the following lines in prpclient.ini:

server=PRS:100:1:prpnet.primegrid.com:12008
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2016 PRPNet August Challenge.

Good luck!

2016-08-06: Intermittent downtime for maintenance

Over the next few hours (or days) I will be bringing down the server briefly to perform some optimizations on the database. This may happen several times.

During the recent challenge, some non-critical functions didn't perform as well as I'd like. Now that the challenge is over, while there's still an extra million tasks in the system is a good time to address those problems.

The server likely will only be down for a minute or two at a time, but if your computer connects to the server when the server is down, your computer will wait an hour before trying to connect again. Therefore, I advise setting your BOINC clients to use a cache of at least an hour so your computer doesn't run out of work if it suspends work requests for an hour.

2016-08-05: Server maintenance

Following completion of the challenge approximately an hour from now, we will be taking the server down for maintenance. The outage is expected to be brief. The entire server will be down, so the forums will be inaccessible. If the outage lasts longer than expected, we'll keep you updated via the chatroom.

2016-08-02: Summer Olypics Challenge Starts August 2nd at 21:00 UTC

Please join us for the Summer Olympics Challenge, running from August 2nd 21:00:00 UTC until August 5th 21:00:00 UTC. This challenge is running the TRP-Sieve app only.

For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=6911

2016-07-20: Oh My! Another PPS Mega Prime!

On 14 July 2016, 18:48:35 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

453*2^3387048+1

The prime is 1,019,606 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 165th overall.

The discovery was made by Andreas Mueller (Andreas) of Germany using an Intel(R) Xeon(R) CPU E5620 @ 2.40GHz with 16GB RAM, running Linux. This computer took about 3 hours 40 minutes to complete the primality test using LLR.

The prime was verified on 14 July 2016, 19:08:33 UTC, by Steve King (steveking) of the United States using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 20GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 20 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-07-20: You Guessed It...Another PPS Mega Prime!

On 25 June 2016, 09:58:06 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

403*2^3334410+1

The prime is 1,003,716 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 172nd overall.

The discovery was made by Roman Trunov (stream) of Russia using an Intel(R) Pentium(R) CPU G860 @ 3.00GHz with 6GB RAM, running Linux. This computer took about 2 hours 44 minutes to complete the primality test using LLR.

The prime was verified on 25 June 2016, 17:18:48 UTC, by Jens Riemann (gemini8) of Germany using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 8GB RAM, running Linux. This computer took about 3 hours 44 minutes to complete the primality test using LLR. Jens is a member of the Rechenkraft.net team.

For more details, please see the official announcement.

2016-07-20: And the PPS Mega Primes Keep on Rolling!

On 24 June 2016, 01:57:14 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

309*2^3577339+1

The prime is 1,076,889 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 119th overall.

The discovery was made by Russell Mathers (Russ) of the United Kingdom using an Intel(R) Core(TM) i7-5960X CPU @ 3.00GHz with 32GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 11 minutes to complete the primality test using LLR.

The prime was verified on 24 June 2016, 21:32:07 UTC, by Jakub Pavlis (JakuP) of the Czech Republic using an Intel(R) Core(TM) i3-2310M CPU @ 2.10GHz with 4GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 55 minutes to complete the primality test using LLR. Jakub is a member of the Czech National Team.

For more details, please see the official announcement.

2016-07-19: Another PPS Mega Prime!

On 22 June 2016, 00:53:21 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

345*2^3532957+1

The prime is 1,063,529 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 130th overall.

The discovery was made by William de Thomas (wdethomas) of Puerto Rico using an Intel(R) Xeon(R) CPU E5-2623 v3 @ 3.00GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 21 minutes to complete the primality test using LLR. William is a member of the Puerto Rico Assisting Science.

For more details, please see the official announcement.

2016-07-19: Another PPS Mega Prime!

On 20 June 2016, 12:52:22 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

323*2^3482789+1

The prime is 1,048,427 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 143rd overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i5-2400S CPU @ 2.50GHz with 4GB RAM, running Microsoft Windows 10 Enterprise. This computer took about 2 hours 23 minutes to complete the primality test using LLR. Scott is a member of the Duke University.

For more details, please see the official announcement.

2016-07-15: Another PPS Mega Prime!

On 23 June 2016, 09:03:40 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

381*2^3563676+1

The prime is 1,072,776 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 125th overall.

The discovery was made by Milan F?a?ek (RNDR. MF1) of the Czech Republic using an Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz with 8GB RAM, running Microsoft Windows 7 Professional. This computer took about 1 hour 22 minutes to complete the primality test using LLR. Milan is a member of the Czech National Team.

The prime was verified on 23 June 2016, 21:44:24 UTC, by Walter Darimont (Walter Darimont) of Belgium using an Intel(R) CPU @ 2.66GHz with 4GB RAM, running Linux. This computer took about 4 hours 26 minutes to complete the primality test using LLR. Walter is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2016-07-15: Another PPS Mega Prime!

On 22 June 2016, 12:49:45 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

351*2^3545752+1

The prime is 1,067,381 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 127th overall.

The discovery was made by Sylvanus A. Zimmerman (Van Zimmerman) of the United States using an Intel(R) Xeon(R) CPU E3-1225 v3 @ 3.20GHz with 2GB RAM, running FreeBSD 10.3. This computer took about 1 hour 27 minutes to complete the primality test using LLR. Sylvanus is a member of the Aggie The Pew team.

The prime was verified on 24 June 2016, 04:28:31 UTC, by user (13G) of the Czech Republic using an Intel(R) Core(TM) i5-2415M CPU @ 2.30GHz with 8GB RAM, running Darwin. This computer took about 2 hours 33 minutes to complete the primality test using LLR. 13G is a member of the Czech National Team.

For more details, please see the official announcement.

2016-07-15: PPS Mega Prime!

On 21 June 2016, 15:59:00 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

329*2^3518451+1

The prime is 1,059,162 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 132nd overall.

The discovery was made by Stefan Larsson (288larsson) of Sweden using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 10. This computer took about 1 hour 20 minutes to complete the primality test using LLR. Stefan is a member of the Sicituradastra. team.

The prime was verified on 23 June 2016, 19:45:48 UTC, by Wiktor Jezioro (Wiktor) of Poland using an Intel(R) Xeon(R) CPU E5-2690 v2 @ 3.00GHz with 30GB RAM, running Linux. This computer took about 1 hour 57 minutes to complete the primality test using LLR. Wiktor is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2016-06-29: ESP Sieve shutting down July 31st

The ESP-Sieve has reached its optimal sieving depth and will be shut down soon. If you're close to that next badge level, now is the time to get it. The actual date will be depend on when work runs out, but we will make sure there's work until at least the 31st.

More information and discussion can be found here: http://www.primegrid.com/forum_thread.php?id=6883

2016-06-14: Summer Solstice Challenge starts 20 June 2016 22:34 UTC

The longest day of the year is drawing near and to mark this turning point in the year, PrimeGrid is offering a 5 day challenge on Proth MEGA Prime Search (LLR). Only PPS MEGA is part of the challenge!

For more information, questions and general banter and merry making please join us on the forums

2016-06-10: Please upgrade your Nvidia drivers!

Recently, Nvidia released driver 368.22 which fixes the serious error introduced with their 364.xx driver. Please upgrade to 368.22 or later, unless you are running Windows XP or Windows Vista.

If you are running the 364.xx or 365.xx drivers, it is imperative that you upgrade to 368.22 or later. The 364.xx and 365.xx drivers can produce incorrect calculation results.

However, if you are running Windows XP or Windows Vista, these versions of Windows are no longer supported by Nvidia's drivers as of 368.22. If you're running XP or Vista, you must revert to an earlier version of the driver (363.xx or earlier).

2016-06-05: SR5 Mega Prime - PrimeGrid's 100th MEGA Prime Find!!!

On 30 May 2016, 18:15:42 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=53546 by finding the mega prime:

53546*5^2216664-1

The prime is 1,549,387 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 48th overall. This is the largest known base 5 mega prime. 75 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Tom Greer (tng*) of the United States using an Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz with 32GB RAM running Microsoft Windows 7 Professional. This computer took about 29 hours 24 minutes to complete the primality test using LLR. Tom is a member of the Sicituradastra. team.

The prime was verified on 2 June 2016, 01:20:10 UTC by John Parker (Mike Parker) of the United States using an Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz with 16GB RAM running Microsoft Windows 10. This computer took about 80 hours 8 minutes to complete the primality test using LLR. John is a member of the SETI.USA team.

For more details, please see the official announcement.

2016-06-04: PRPNet June Challenge

ESCO 2016 Computing Challenge

Announced is a PRPNet challenge at the 121 prime search project from the 5th till 12th of June.
Work in PRPNet counts towards your PSA badge.
Leading edge of the search now up to 6,776,241 on both the plus and minus side. Goal will be to get both to 6.85M.
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=121:100:1:prpnet.primegrid.com:12001
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2016 PRPNet June Challenge.

Good luck!

2016-05-22: Another PPS Mega Prime!

On 16 May 2016, 07:12:37 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

373*2^3404702+1

The prime is 1,024,921 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 152nd overall.

The discovery was made by Seonghwan Kim (ext2097) of South Korea using an Intel(R) Xeon(R) CPU E3-1231 v3 @ 3.40GHz with 4GB RAM, running Linux. This computer took about 56 minutes to complete the primality test using LLR. Seonghwan is a member of the SETIKAH@KOREA team.

The prime was verified on 17 May 2016, 01:25:38 UTC, by Bob Bussard (RGB) of Canada using an Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz with 8GB RAM, running Microsoft Windows 8.1. This computer took about 3 hours 39 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-05-22: Another PPS Mega Prime!

On 9 May 2016, 13:07:05 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

303*2^3391977+1

The prime is 1,021,090 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 154th overall.

The discovery was made by Andreas Mueller (Andreas) of Germany using an Intel(R) Pentium(R) CPU G2130 @ 3.20GHz with 8GB RAM, running Microsoft Windows 7 Enterprise. This computer took about 2 hours 28 minutes to complete the primality test using LLR.

The prime was verified on 12 May 2016, 16:24:32 UTC, by Stephane Guichard (stef71000) of France using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 31 minutes to complete the primality test using LLR. Stephane is a member of the L'Alliance Francophone team.

For more details, please see the official announcement.

2016-05-09: GFN-262144 Mega Prime May Edition!

On 4 May 2016, 10:57:07 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1615588^262144+1

The prime is 1,627,477 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 44th overall.

The discovery was made by Brook Harste (brinktastee) of the United States using an NVIDIA GeForce GTX 980 Ti in an Intel(R) Core(TM) i7-3820 CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional. This GPU took about 17 minutes to probable prime (PRP) test with GeneferOCL4. Brook is a member of the Aggie The Pew team.

The prime was verified on 8 May 2016, 15:28:12 UTC by Rรณbert Borbรฉly (SosRud) of Hungary using an AMD Cypress in an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional. This GPU took about 1 hour and 36 minutes to probable prime (PRP) test with GeneferOCL4.

For more details, please see the official announcement.

2016-05-09: PPS Mega Prime!

On 10 April 2016, 19:53:20 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

369*2^3365614+1

The prime is 1,013,154 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 155th overall.

The discovery was made by Will Steinbach (bill1024) of the United States using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 32GB RAM, running Linux. This computer took about 1 hour 36 minutes to complete the primality test using LLR. Will is a member of the Crunching@EVGA team.

The prime was verified on 10 April 2016, 20:58:16 UTC, by Stephen Norton (spnorton) of the United States using an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 7 Professional. This computer took about 2 hour 52 minutes to complete the primality test using LLR. Stephen is a member of the Alien Prime Cult team.

For more details, please see the official announcement.

2016-04-16: Trouble with Nvidia's 364.xx driver

Numerous participants have had tasks fail due the Nvidia's buggy 364.xx driver. If you're using this driver, I recommend reverting to an earlier version of the driver with a major version number lower than 364.

If you're currently running an older version of the driver, I strongly recommend that you do not "upgrade" to 364.xx. I've also heard reports of this driver "bricking" GPUs, and that goes way, way beyond merely having some BOINC tasks fail.

2016-04-15: SR5 Mega Prime - March 2016 Edition Version 3.0

On 25 March 2016, 10:34:36 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=296024 by finding the mega prime:

296024*5^2185270-1

The prime is 1,527,444 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 50th overall. This is the largest known base 5 mega prime. 76 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Steven Wong (mackerel) of the United Kingdom using an Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz with 16GB RAM running Microsoft Windows 10. This computer took about 15 hours 10 minutes to complete the primality test using LLR. Steven is a member of the Aggie The Pew team.

The prime was verified on 29 March 2016, 09:01:18 UTC by Matthew Borneman (Maxwell [MM]) of the United States using an Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz with 4GB RAM running Microsoft Windows 7 Professional. This computer took about 65 hours 5 minutes to complete the primality test using LLR. Matthew is a member of the SETI.USA team.

For more details, please see the official announcement.

2016-04-09: Cullen Birthday Challenge starts April 19th 2016, 18:00:00 UTC

To celebrate the 149th birthday of James Cullen, the namesake of the Cullen primes we're looking for at PrimeGrid, we are hosting a 9 day challenge. This challenge starts on April 19th 18:00 UTC, his birthday.

For more information, questions and general banter and merry making please join us on the forums

2016-03-30: GFN-262144 Mega Prime March Edition!

On 5 March 2016, 18:56:52 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1488256^262144+1

The prime is 1,618,131 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 43rd overall.

The discovery was made by Stefan Larsson (288larsson) of Sweden using an AMD Hawaii in an Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz with 8GB RAM, running Linux. This GPU took about 27 minutes to probable prime (PRP) test with GeneferOCL4. Stefan is a member of the Sicituradastra. team.

The prime was verified on 5 March 2016, 19:25:40 UTC by Dirk Kraemer (DoctorNow) of Germany using an NVIDIA GeForce GTX 760 in an AMD Phenom(tm) II X6 1045T Processor with 12GB RAM, running Windows Vista Home Premium. This GPU took about 1 hour and 5 minutes to probable prime (PRP) test with GeneferOCL3. Dirk is a member of the BOINC Confederation team.

For more details, please see the official announcement.

2016-03-30: PPS Mega Prime!

On 24 March 2016, 00:45:48 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

393*2^3349525+1

The prime is 1,008,311 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 153rd overall.

The discovery was made by Timothy Reichard (Timothy Reichard) of the United States using an Intel(R) Core(TM) i7-4960HQ CPU @ 2.60GHz with 16GB RAM, running Darwin. This computer took about 1 hour 10 minutes to complete the primality test using LLR.

The prime was verified on 24 March 2016, 00:58:33 UTC, by Alex Huetter (ahlx) of Austria using an Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz with 4GB RAM, running Microsoft Windows 10 Professional. This computer took about 1 hour 14 minutes to complete the primality test using LLR. Alex is a member of the Gentoo Linux Users Everywhere team.

For more details, please see the official announcement.

2016-03-30: SR5 Mega Prime - March 2016 Edition Version 2.0

On 15 March 2016, 18:24:24 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=92158 by finding the mega prime:

92158*5^2145024+1

The prime is 1,499,313 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 53rd overall. This is the largest known base 5 mega prime. 33 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Karl Burridge (Aus_Karlos) of Australia using an Intel(R) Core(TM) i7 CPU 950 @ 3.07GHz with 8GB RAM running Linux. This computer took about 43 hours 17 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-03-30: SR5 Mega Prime - March 2016 Edition

On 6 March 2016, 07:54:42 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=77072 by finding the mega prime:

77072*5^2139921+1

The prime is 1,495,746 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 53rd overall. This is the largest known base 5 mega prime. 34 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Wolfgang Becker (flex) of Germany using an Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz with 4GB RAM running Windows 10 Professional. This computer took about 10 hours 42 minutes to complete the primality test using LLR. Wolfgang is a member of the BOINC@Heidelberg team.

The prime was verified on 9 March 2016, 22:19:31 UTC by Magnus Karlsteen (pep) of Sweden using an Intel(R) Xeon(R) CPU X5690 @ 3.47GHz with 24GB RAM running Windows 7 Professional. This computer took about 9 hours 9 minutes to complete the primality test using LLR.


For more details, please see the official announcement.

2016-03-24: PRPNet April Challenge

Join us over at the Generalized Cullen/Woodall prime search from the 1st till 8th of April to help celebrate Mathematics Awareness Month.
This years theme is "The Future of Prediction"!
Discussion and more information can be found here: 2016 PRPNet April Challenge.

Good luck!

2016-03-13: From Pi to Paddy Challenge starts March 14th, 03:14:15 UTC

March sees two celebrations, one mostly celebrated by mathematicians the other recognized by a broader part of western society. March 14th is Pi-day, as the approximation starts with 3.14. which could read as March 14th. The other festivity is Saint Patrick's day, which finds its origin in Ireland but is celebrated now in many countries across the world.

To participate in these celebrations, we are hosting a 3 day challenge on the SR5 subproject. Please note the non-standard starting time!

For more information, questions, banter and cursing me for being quite late with information about this challenge please do join us on the forums.

2016-03-06: World Record Sophie Germain Prime!

On 29 February 2016 05:39:14 UTC, PrimeGrid?s Sophie Germain Prime Search found a World Record Sophie Germain prime: 2618163402417*2^1290000-1 (2p+1: 2618163402417*2^1290001-1)

The prime is 388,342 digits long, eclipsing the previous record of 200,701 digits. It enters Chris Caldwell's ?The Largest Known Primes Database? ranked 1st for Sophie Germain primes and 3,747th overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM)2 Quad CPU Q6700 @ 2.66GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer, using LLR, took about 1 hour and 33 minutes to complete the primality test. Scott is a member of the Duke University team.

The prime was verified on 29 February 2016 06:21:47 UTC, by Vaughan Davies (vaughan) of Australia using an Intel(R) Core(TM) i7-4770S CPU @ 3.10GHz with 32 GB RAM running Microsoft Windows 7 Ultimate. This computer, using LLR, took about 47 minutes to complete the primality test. Vaughan is a member of the AMD Users team.

For more details, please see the official announcement.

2016-03-02: GeneferCUDA apps to be shut down permanently

When the upcoming GeneferOCL v3.3.0 apps are live, we will be permanently shutting down the GeneferCUDA apps.

More details are available in the Deprecating GeneferCUDA thread.

If there's a reason why you want to keep running GeneferCUDA, now is the time to speak up. Once we shut off GeneferCUDA it will be too late.

2016-03-02: LLR 3.8.17 is now live on all LLR projects

As of a short time ago, all LLR apps have been upgraded to BOINC version 7.06, which uses LLR 3.8.17.

If you're not using app_info (aka "anonymous platform"), or don't know what that means, no action is necessary on your part. BOINC will do the update automatically.

If you are using app_info in order to run LLR 3.8.17, it's no longer necessary to use app_info and you may, if you wish, switch back to using the stock apps.

If you are using app_info but are using an older version of LLR, you should update to the new version of LLR.

For more information please see the LLR 3.8.17 Testing thread.

2016-03-02: PRPNet March Challenge

Join us over that the Wall-Sun-Sun prime search from the 2nd till 9th of March for the World Maths Day Challenge!
Discussion and more information can be found here: 2016 PRPNet March Challenge.

Good luck!

2016-02-28: Another GFN-131072 Mega Prime!

On 25 February 2016, 02:26:37 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

43165206^131072+1

The prime is 1,000,753 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th for Generalized Fermat primes and 154th overall.

The discovery was made by Alen Kecic (Freezing) of Germany using an NVIDIA GeForce GTX 660 Ti in an Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz with 8GB RAM, running Windows 7 Professional. This GPU took 52 minutes to probable prime (PRP) test with GeneferOCL2. Alen is a member of the SETI.Germany team.

The prime was verified on 26 February 2016, 02:40:45 UTC by [CSF] Joris Degraide of France using an NVIDIA GeForce GTX 970M in an Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz with 16GB RAM, running Windows 7 Ultimate. This GPU took 48 minutes to probable prime (PRP) test with GeneferOCL2. [CSF] Joris Degraide is a member of the CRUNCHERS SANS FRONTIERES team.

For more details, please see the official announcement.

2016-02-28: GFN-131072 Mega Prime!

On 24 February 2016, 20:53:55 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

43163894^131072+1

The prime is 1,000,751 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 16th for Generalized Fermat primes and 154th overall.

The discovery was made by David E. Miller (dem0707) of the United States using an NVIDIA GeForce GTX 980 in an Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz with 16GB RAM, running Windows 7 Professional. This GPU took about 26 minutes to probable prime (PRP) test with GeneferOCL2. David is a member of the Crunching@EVGA team.

The prime was verified on 24 February 2016, 21:37:52 UTC by Alen Kecic (Freezing) of Germany using an NVIDIA GeForce GTX 660 Ti in an Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz with 8GB RAM, running Windows 7 Professional. This GPU took 48 minutes to probable prime (PRP) test with GeneferOCL2. Alen is a member of the SETI.Germany team.

For more details, please see the official announcement.

2016-02-26: Another PPS Mega Prime!

On 24 February 2016, 12:04:12 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

189*2^3596375+1

The prime is 1,082,620 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 106th overall.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) Xeon(R) CPU E5-1630 v3 @ 3.70GHz with 16GB RAM, running Microsoft Windows 7 Professional. This computer took about 58 minutes to complete the primality test using LLR. Hiroyuki is a member of the Aggie The Pew team.

The prime was verified on 24 February 2016, 13:18:01 UTC, by user Shaman of the Czech Republic using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Microsoft Windows 7 Professional. This computer took about 2 hours 2 minutes to complete the primality test using LLR. Shaman is a member of the Czech National Team team.

For more details, please see the official announcement.

2016-02-26: PPS Mega Prime!

On 21 February 2016, 16:55:42 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

387*2^3322763+1

The prime is 1,000,254 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 152nd overall.

The discovery was made by Sami Heikkilรค (samuel7) of Finland using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 10. This computer took about 1 hour 6 minutes to complete the primality test using LLR. Sami is a member of the PrimeSearchTeam team.

The prime was verified on 24 February 2016, 15:14:59 UTC, by William Donovan (Williamd007) of the United States using an AMD FX(tm)-9590 Eight-Core Processor with 16GB RAM, running Microsoft Windows 10. This computer took about 2 hours 27 minutes to complete the primality test using LLR. William is a member of the The Knights Who Say Ni! team.

For more details, please see the official announcement.

2016-02-24: GFN-262144 Mega Prime!

On 16 February 2016, 16:45:20 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

1415198^262144+1

The prime is 1,612,400 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 5th for Generalized Fermat primes and 43rd overall.

The discovery was made by Frank Matillek (boss) of Germany using an NVIDIA GeForce GTX 660 Ti in an Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHz with 4GB RAM, running Windows 7 Ultimate. This GPU took about 53 minutes to probable prime (PRP) test with GeneferOCL3. Frank is a member of the SETI.Germany team.

The prime was verified on 16 February 2016, 17:01:20 UTC by Alan Kong (Wingless Wonder) of the United States using an NVIDIA GeForce GTX Titan Black in an Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz with 32GB RAM, running Windows 10 Professional. This GPU took 30 minutes to probable prime (PRP) test with GeneferOCL3. Alan is a member of the AMD Users team.

For more details, please see the official announcement.

2016-02-17: PPS Mega Prime!

On 9 February 2016, 02:47:35 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

275*2^3585539+1

The prime is 1,079,358 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 104th overall.

The discovery was made by Tyler Bredl (1998golfer) of the United States using an Intel(R) Xeon(R) CPU E5-2666 v3 @ 2.90GHz with 60GB RAM, running Linux. This computer took about 3 hour 3 minutes to complete the primality test using LLR. Tyler is a member of the Aggie The Pew team.

The prime was verified on 9 February 2016, 22:55:34 UTC, by Andreas Mueller (Andreas) of Germany using an Intel(R) Xeon(R) CPU E5620 @ 2.40GHz with 16GB RAM, running Linux. This computer took about 3 hours 51 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2016-02-01: PPS Mega Prime!

On 25 January 2016, 11:24:35 UTC, PrimeGrid?s PPS Mega Prime Search project found the Mega Prime:

251*2^3574535+1

The prime is 1,076,045 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 105th overall.

The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 42 minutes to complete the primality test using LLR.

The prime was verified on 25 January 2016, 23:32:54 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 8GB RAM, running Microsoft Windows 7 Enterprise. This computer took about 59 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2016-02-01: SR5 Mega Prime - January 2016 Edition

On 11 January 2016, 10:02:08 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=306398 by finding the mega prime:

306398*5^2112410-1

The prime is 1,476,517 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 50th overall. This is the largest known base 5 mega prime. 77 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Andrรฉ Ahlfors Dahl (NocFlame) of Sweden using an Intel(R) Xeon(R) CPU W3520 @ 2.67GHz with 16GB RAM running Linux. This computer took about 77 hours 10 minutes to complete the primality test using LLR. Andrรฉ is a member of the Gridcoin team.

The prime was verified on 17 January 2016, 19:36:26 UTC by evaotaku00 of the United States using an Intel(R) Xeon(R) CPU X5355 @ 2.66GHz with 24GB RAM running Darwin. This computer took about 77 hours 10 minutes to complete the primality test using LLR. evaotaku00 is a member of the Ars Technica team.

For more details, please see the official announcement.

2016-02-01: SR5 Mega Prime - November 2015 Edition

On 10 November 2015, 07:16:15 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=154222 by finding the mega prime:

154222*5^2091432+1

The prime is 1,461,854 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 51st overall. This is the largest known base 5 mega prime. 35 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Xeon(R) CPU E5-1620 v3 @ 3.50GHz with 16GB RAM running Windows 10 Professional. This computer took about 5 hours and 5 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.


For more details, please see the official announcement.

2016-01-31: Tour de Primes 2016

In less than 24 hours, it will be February -- and that means it's time for the 2016 Tour de Primes Challenge!

Unlike other challenges, there's no trophy for participation. This challenge is all about finding prime numbers.

For 2016, we've added a new trophy -- the red jersey -- which will be awarded to whomever finds the largest prime number during the month of February.

And, of course, we'll be awarding the green, yellow, and polk-a-dot jerseys as in previous years.

For more information, please see Tour de Primes 2016.

Good luck everyone!

2016-01-01: Makar Sankranti Challenge starts January 7th 18:00:00 UTC

Makar Sankranti is a Hindu festival celebrated in almost all parts of India and Nepal in a myriad of cultural forms. Makar Sankranti marks the transition of the Sun into the zodiac sign of Makara rashi (Capricorn) on its celestial path. The day is also believed to mark the arrival of spring in India and is a traditional event. Makara Sankranthi is a solar event making one of the few Indian festivals which fall on the same date in the Gregorian calendar every year: 14 January, with some exceptions when the festival is celebrated on 13 or 15 January.

To warm up for this festival PrimeGrid is offering a an 8 day challenge on some of Generalized Fermat Number prime search. From January 7th 18:00:00 UTC until January 15th 18:00:00 UTC we will have an 8 day challenge running several Generalized Fermat Prime Search Projects.

These GFN-projects are part of the challenge:
GFN-17 MEGA
GFN-18
GFN-19
GFN-20
GFN-21
GFN-WR


These GFN-projects are NOT part of the challenge:
GFN-15
GFN-16
GFN-17 LOW


For more information, questions and general banter and merry making please join us on the forums

2015-12-04: GFN=15 (32768) Switching to OCL2 soon

In about a week, GFN 15 (32768) will switch from OCL3 to OCL2.

IMPORTANT: Some GPUs can not run OCL2!!!

Older Nvidia GPUs that are below CC 2.0 will not work.

ATI/AMD GPUs, on Mac only, will not work.

For more details and discussion, please see this thread.

2015-12-04: GFN=15 (32768) Switching to OCL2 soon (DONE)

:::::::::: EDIT: GFN15 has been switched to OCL2. ::::::::::


In about a week, GFN 15 (32768) will switch from OCL3 to OCL2.

IMPORTANT: Some GPUs can not run OCL2!!!

Older Nvidia GPUs that are below CC 2.0 will not work.

ATI/AMD GPUs, on Mac only, will not work.

For more details and discussion, please see this thread.

2015-12-02: Winter Solstice Challenge starts Dec 19th, 04:48 UTC

The end of the year is drawing closer and this is traditionally marked with the winter solstice challenge here at PrimeGrid. As in previous years we would like to invite everyone to join us in this celebration of tidings of comfort and joy by sieving away for the Proth Prime Search. The challenge will start on Dec 19 04:48 UTC and last for 72 hours.

For more information, cheery banter and general merrymaking please join us on the discussion board.

We hope to see you there and please do spread the word :)

2015-12-01: PRPNet December Challenge

Join us over that the 121 prime search from the 1st till 11th of December for the Binomial Challenge and help celebrate the life of Omar Khayyรกm.
Discussion and more information can be found here: 2015 PRPNet December Challenge.
?Never tell me the odds.? ? Han Solo

2015-11-17: PRPNet November Challenge

Join us over that the GCW prime search from the 21st till 28th of November for a Snark Hunt.
First we are searching base 47 to One Million. Will we catch the Snark or will it turn out to be a highly dangerous Boojum?
Discussion and more information can be found here: 2015 PRPNet November Challenge.

Good luck!

2015-11-11: GFN-131072 Mega Prime!

On 9 Nov 2015, 18:02:51 UTC, PrimeGrid?s Generalized Fermat Prime Search found the Generalized Fermat mega prime:

42654182^131072+1

The prime is 1,000,075 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th for Generalized Fermat primes and 143rd overall. Of note, this find appears to be the first Titanic prime (>= 1000 digits) found using fixed-point numbers.

The discovery was made by Andrew M. Farrow (Nortech) of Australia using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i3-4170 CPU @ 3.70GHz with 4GB RAM running Linux. This GPU took about 1 hour 2 minutes to probable prime (PRP) test with GeneferOCL2.

The prime was verified by Patrick Schรถfer (pschoefer) of Germany using an NVIDIA GeForce GTX 660 Ti in an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 16GB RAM running Windows 7 Professional. This computer took about 47 minutes to probable prime (PRP) test with GeneferOCL2. Patrick is a member of the SETI.Germany team.

For more details, please see the official announcement.

2015-11-08: Leonids Showers Challenge starts November 14th, 18:00 UTC

Watch out, winter is coming! (On the northern hemisphere at least) Although winter has some good sides, all the cold and what not is only good to push your crunchers to the maximum. PrimeGrid is therefore more than happy to oblige and offer a 3 day challenge on Sophie Germain Prime Search (LLR), coinciding with the Leonids Meteor Shower. Be careful with pushing your machines though, wouldn't want to turn it into a meteor!

The challenge starts on November 14th, 18:00 UTC.

For more information, questions and answers join us on the forums

2015-11-05: New LLR app (7.05) released

A new app (7.05) has been released for all LLR projects. LLR itself is the same, but the wrapper's trickle logic is improved.

The discussion thread is here.

2015-11-05: PPS Mega Prime!

On 30 October 2015, 03:27:00 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

191*2^3548117+1

The prime is 1,068,092 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 105th overall.

The discovery was made by Roman Azarenko (Roman Azarenko) of Russia using an Intel(R) Xeon(R) CPU E3-1240 v3 @ 3.40GHz with 2GB RAM, running Linux. This computer took about 1 hour 7 minutes to complete the primality test using LLR. Roman is a member of the Russia Team.

The prime was verified on 2 November 2015, 22:02:26 UTC, by Jon Beard (Fuzzy Duck) of Vietnam using an Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz with 32GB RAM, running Microsoft Windows 10. This computer took about 7 hours 1 minute to complete the primality test using LLR. Jon is a member of the The Knights Who Say Ni! team.

For more details, please see the official announcement.

2015-11-04: GFN 262144, GFN 524288, and GFN 1048576 Now Open!

The last three GFN ranges have been reopened on the BOINC server, and the corresponding GFN 262144 and GFN 524288 PRPNet ports have been shut down.

Details and discussion can be found in this thread.

2015-11-04: Genefer 3.2.9 released for n=4194304 and n=2097152

I have put Genefer 3.2.9 into production on the n=21 and n=22 (World Record) projects. (3.2.9 was already running on n=15, n=16, and n=17.)

This may affect you in the following ways:
If you use app_info, you should update your configuration to use the new 3.2.9 apps if you're not already doing so. (If you're not using app_info, or don't know what app_info is, no action is necessary on your part.) N=21 and N=22 (WR) will now use trickles to extend deadlines. Because the deadline extension mechanism is now functional on n=21, the deadline has been lowered back to 21 days. The max deadline is unchanged at 84 days, so effectively you now have twice as much time to complete the task while abandoned tasks will be resent in half the time.

Discussion about this release is in this thread.

2015-11-03: Leonids Showers Challenge starts November 14th, 18:00 UTC

Watch out, winter is coming! (On the northern hemisphere at least) Although winter has some good sides, all the cold and what not is only good to push your crunchers to the maximum. PrimeGrid is therefore more than happy to oblige and offer a 3 day challenge on Sophie Germain Prime Search (LLR), coinciding with the Leonids Meteor Shower. Be careful with pushing your machines though, wouldn't want to turn it into a meteor!

The challenge starts on November 14th, 18:00 UTC.

For more information, questions and answers join us on the forums

2015-10-28: Scheduled PRPNet downtime on Thursday (10/29) UTC

The first maintenance period has been completed, and as previously discussed, later tonight or tomorrow, depending on your time zone, PrimeGrid's PRPNet server will go down for preventive maintenance. We will take the server down at about 2015-10-29 02:55:00 UTC (10:55 PM EDT Wednesday night). If all goes according to plan, PRPNet should be back up no later than 05:00:00 UTC.

During this outage, PRPNet will be disabled, and your PRPNet clients will not be able to reach the server. Web pages on the various PRPNet ports will also be unavailable. Please plan accordingly.

BOINC (including forums and this website) will not be affected.

We will also be doing maintenance on the BOINC database replica during the same 03:00:00 UTC to 05:00:00 UTC window. We do not anticipate this affecting users.

Discussion thread is located here.

2015-10-27: Scheduled downtime on Wednesday 10/28

As previously discussed, later tonight or tomorrow, depending on your time zone, PrimeGrid's main server will go down for preventive maintenance. We will take the server down at about 2015-10-28 06:55:00 UTC (2:55 AM EDT). If all goes according to plan, we should be back up no later than 09:00:00 UTC.

During this outage, all web access to www.primegrid.com will be disabled, and your BOINC clients will not be able to reach the server. Please plan accordingly.

PRPNet will not be affected.

Since the forums will not be available, I suggest using our chatroom. This is why we have an external chatroom -- for keeping in touch if the main system is down. Note that this is the middle of the night for Jim and myself, so we probably won't be very talkative.

Discussion thread is located here.

2015-10-26: SR5 Mega Prime!

On 21 October 2015, 05:23:34 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=100186 by finding the mega prime:

100186*5^2079747-1

The prime is 1,453,686 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 53rd overall. This is the largest known base 5 mega prime. 78 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Toshitaka Kumagai (Toshitaka Kumagai) of Japan using an Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz with 32GB RAM running Linux. This computer took about 15 hours 41 minutes to complete the primality test using LLR.

The prime was verified on 21 October 2015, 18:46:14 UTC by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 8GB RAM running Microsoft Windows 7 Enterprise. This computer took about 27 hours 36 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2015-10-25: Scheduled downtime on Wednesday (10/28) and Thursday (10/29)

There will be some scheduled downtime for maintenance on Wednesday, October 28th between 07:00:00 UTC and 09:00:00 UTC, and also on Thursday, October 29th between 03:00:00 UTC and 05:00:00 UTC.

Please follow this forum thread for more details and for updated information.

2015-10-16: GFN 131072 (Low) and GFN 131072 (Mega)

We have opened up the n=17 (131072) GFN range on BOINC -- not just once, but twice!

In addition to the normal 131072 (aka "Low") range, we've also opened up a second 131072 range starting at a very high b -- just high enough so the numbers are at least a million digits long. Since these are crunchable with the new OCL2 GPU app, this makes it one of the fastest mega-prime searches available.

For discussion or more information, please click here.

2015-10-13: GFN 32768 and GFN 65536 now available on BOINC

Generalized Fermat Number (GFN) tests with n=32768 and n=65536 are now available on BOINC by selecting the appropriate tasks under "PrimeGrid Preferences".

Both CPU and GPU tasks are available. Initially, we're double checking earlier work that was only single checked.

More details can be found here.

2015-10-06: PRPNet October Challenge

Join us over that the Wall-Sun-Sun prime search from the 10th till 30th of October.
The Coma Wall is the largest Wall in the Universe and we'll be using this Wall of Sun's as the theme of the challenge.
Discussion and more information can be found here: 2015 PRPNet October Challenge.

Good luck!

2015-10-01: World Animal Day starts October 4th, 2015, 18:00 UTC

People have always had an interesting relationship with animals. We hunt them for food, we keep livestock for food too but we also use them for labor and keep them as pets and love them like family. In honor of this relationship there is a special day, World Animal Day. To mark this day, PrimeGrid invites every one to participate in the challenge starting at 18:00 utc on October 4th, 2015 it will run for five days until October 9th, 2015, 18:00 UTC

For questions, banter, information you can go to this thread in our forums.

Please do spread the word and join the fun!

2015-09-19: PRPNet September Challenge

Tolkien Week Challenge

Announced is a PRPNet challenge at the Wieferich prime search project from the 19th until the 26th of September. Come and celebrate Tolkien Week over at the Shire with Bilbo and Frodo Baggins. Who knows, YOU might discover the One Ring (A = 0).
Discussion and more information can be found here: 2015 PRPNet September Challenge.

?All we have to decide is what to do with the time that is given us.?
? J.R.R. Tolkien, The Fellowship of the Ring

2015-09-15: Tell the White House about BOINCand PrimeGrid

The White House is staging a webcast forum on citizen science on Sept. 30. Let's make sure that BOINC, PrimeGrid and volunteer computing are represented in this event! Please tell the White House about your experience with volunteer computing, and why it's important.

Discussion thread is here.

(Original post located here.)

2015-09-15: GFN-Short is... not so short anymore

The GFN-Short project has completed its double-checking diversion and has moved on to its next and permanent n-range: n=21 (2097152)

These tasks are HUGE. Not quite as large as the world record tasks, but still very large. Calling them "Short" would make even an advertising executive blush. So "Short" is out. This is now the "GFN-21" project.

Expect run times to be about 15-20 hours for a fairly fast GPU (and just under 10 for the very fastest). Expect about 75 hours for FMA3 capable Haswell CPUs, and about 130 hours for fast modern CPUs without AVX (which unfortunately includes all AMD CPUs, since their AVX instruction set is almost useless.)

Time estimates are based on a single task running, so expect somewhat longer times if you're loading up all the cores. And, as always, your mileage may vary.

Also, expect run times to grow relatively quickly as 'b' grows in magnitude.

The deadline for these tasks is currently a whopping 42 days -- much longer than the times mentioned above for relatively modern computers. Slow computers, old computers, part time crunchers, and so on should still be able to meet the deadline. Once we release the "deadline extension" version of the Genefer app we'll lower the deadline which will give us a faster turnaround for abandoned tasks.

At the current time, this temporarily leaves us without any true short GFN tasks on the BOINC server, but we will be opening up additional n-ranges in the near future with a wide range of much shorter tasks.

Happy crunching!

(All things GFN can be discussed here: http://www.primegrid.com/forum_forum.php?id=75)

2015-09-08: PPS Mega Prime - September Edition!

On 1 September 2015, 05:57:32 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

141*2^3529287+1

The prime is 1,062,424 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 108th overall.

The discovery was made by Chris Hoefliger ({CurlY BracketS}) of Switzerland using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows Professional 8.1. This computer took about 3 hours 9 minutes to complete the primality test using LLR.

The prime was verified on 1 September 2015, 08:36:00 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 8GB RAM, running Microsoft Windows 7 Enterprise. This computer took about 1 hour and 14 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2015-09-06: Reign Record Challenge starts September 10th, 18:00 UTC

We here at PrimeGrid love our records! To celebrate that Queen Elizabeth II will (most likely) be the longest reigning monarch of Great Britain as of September 10th, PrimeGrid is hosting a a 5 day challenge on the Cullen LLR subproject.

For more information, questions, answers and banter please join us on the forum

2015-08-28: New LLR apps and deadline extensions

All LLR projects (SGS, CUL, WOO, PPS, PPSE, PPS-MEGA, 321, SoB, PSP, ESP, TRP, SR5) have been upgraded to version 7.03.

If you're using app_info, aka anonymous platform, you'll definitely want to upgrade your apps to get the latest wrapper AND llr executables. The llr.ini file is unchanged.

The new wrapper does trickle-ups to facilitate automatic deadline extensions if your computer is running late. Please see this thread for details.

The new LLR version fixes some error handling and resolves a problem where tests near FFT boundaries might run much slower than expected. LLr 3.8.16 is discussed in this thread.

Please let us know if there's any problems in this thread.

2015-08-19: PPS Mega Prime!

On 2 August 2015, 07:43:42 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

135*2^3518338+1

The prime is 1,059,128 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 107th overall.

The discovery was made by Evelyn Chew (Crackenback) of Australia using an Intel(R) Xeon(R) CPU E5-2603 0 @ 1.80GHz with 8GB RAM, running Microsoft Windows Server 2008. This computer took about 2 hours 57 minutes to complete the primality test using LLR. Evelyn is a member of the BOINC@AUSTRALIA team.

The prime was verified on 2 August 2015, 09:09:01 UTC, by Paulo Silva (Cyph3r) of Portugal using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 60GB RAM, running Linux. This computer took about 3 hour and 25 minutes to complete the primality test using LLR. Paulo is a member of the Portugal@Home team.

For more details, please see the official announcement.

2015-08-12: PRPNet August Challenge

George Boole Bicentenary Challenge

Announced is a PRPNet challenge at the Primorial prime search project from the 14th until the 28th of August.
Leading edge of the search now up to 1,961,321 on both the plus and minus side. Goal will be to get to 2M.
More about the Primorial prime search can be found here. News and infos about the PRPNet client can be found here.
To take part, you have to activate the following lines in prpclient.ini:
server=PRS:100:1:prpnet.primegrid.com:12008
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2015 PRPNet August Challenge.

Good luck!

2015-08-02: Perseid Shower Challenge starts August 10th 18:00:00 UTC

The night sky can offer some wonderful sights, like distant stars and planets, the milkyway but also meteor showers. The perseids are a prolific meteor shower associated with the comet Swift-Tuttle. To celebrate this wonderful sight, PrimeGrid is running a challenge on the Riesel Problem Sieve subproject. It will start on 10 august 2015 at 18:00 UTC and will run until 12 august 2015, 18:00 UTC.

We hope to welcome many of you in this fun challenge and if you have any questions or just want some banter, please do join us in this thread on our forums.

2015-07-12: 321 Mega Prime! (2015 Edition, part 2)

On 23 June 2015 20:49:21 UTC, PrimeGrid?s 321 Prime Search project found the mega prime:

3*2^11895718-1

The prime is 3,580,969 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 12th overall. This is the largest known 321 mega prime and the largest prime found to date at PrimeGrid!

The discovery was made by Michael Schulz (Michael Schulz) of Germany using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 16 GB RAM running Darwin 14.3.0. This computer took about 9 hours and 57 minutes to complete the primality test using LLR.

The prime was verified on 27 June 2015 3:56:03 UTC, by user Matthew of New Zealand using an Intel(R) Core(TM) i7-4510U CPU @ 2.00GHz with 8 GB RAM running Windows 7 Professional. This computer took about 33 hours and 40 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2015-06-29: SR5 Mega Prime!

On 23 May 2015, 17:47:52 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=144052 by finding the mega prime:

144052*5^2018290+1

The prime is 1,410,730 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 36 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Wolfgang Schmidt (Artist) of Germany using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 16GB RAM running Linux. This computer took about 6 hours and 17 minutes to complete the primality test using LLR. Wolfgang is a member of the Special: Off-Topic team.

The prime was verified on 26 May 2015, 17:48:33 UTC, by user RoBorg of the United Kingdom using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 8GB RAM running Microsoft Windows 7 Professional. This computer took about 15 hours and 24 minutes to complete the primality test using LLR. RoBorg is a member of the Brony@Home team.

For more details, please see the official announcement.

2015-06-24: Another PPS Mega Prime!

On 10 May 2015, 02:13:21 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

195*2^3486379+1

The prime is 1,049,507 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 109th overall.

The discovery was made by Naoki Yoshioka (oevrtaker@biomaterial) of Japan using an Intel(R) Xeon(R) CPU E5-2687W 0 @ 3.10GHz with 64GB RAM running Microsoft Windows 8.1 Enterprise. This computer took about 1 hour and 32 minutes to complete the primality test using LLR. Naoki is a member of the Doshisha University team.

The prime was verified on 10 May 2015, 10:12:42 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 8GB RAM, running Microsoft Windows 7 Enterprise. This computer took about 1 hour and 14 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2015-06-20: PRPNet Solstice Challenge

Feel like finding a Prime? Join us over at the GFN65536 Solstice Challenge.
Runs from 20-27th of June, 12:00 UTC to 12:00 UTC.

The GFN n=16 sub-project currently has 61,447 WUs to go till b=4,000,000, expecting on average 4.8 primes in that range.
My X6 1100T CPU can crunch ~55 WUs per day, giving me a 3% chance of finding a prime during the challenge, (7*4.8*55)/61447=0.03.
I am sure you've got an even better chance.

Remember to enjoy your local Midsummer/winter day festival or go build a Henge!

Discussion and more information can be found here: 2015 PRPNet June Challenge.

Good luck!

2015-06-16: Putting the "Short" back in GFN-Short

The GFN-Short project has just about reached the end of the n=20 range of GFN tasks and is transitioning to n=17 tasks. The n=17 tasks are about 60 times shorter than n=20.

It will take a couple of months for all of the older n=20 work units to complete, so even after the n=17 tasks start going out it will still be possible to get the occasional n=20 task.

The new n=17 tasks will have a 4 day deadline.

For more details and discussion, please see this forum thread.

2015-06-16: PPS Mega Prime!

On 10 May 2015, 00:56:17 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

249*2^3486411+1

The prime is 1,049,517 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 109th overall.

The discovery was made by Evelyn Chew (Crackenback) of Australia using an Intel(R) Pentium(R) CPU G3220 @ 3.00GHz with 4GB RAM running Microsoft Windows 7 Enterprise. This computer took about 2 hours 37 minutes to complete the primality test using LLR. Evelyn is a member of the BOINC@AUSTRALIA team.

The prime was verified on 10 May 2015, 09:36:32 UTC, by Naoki Yoshioka (oevrtaker@biomaterial) of Japan using an Intel(R) Xeon(R) CPU E5-2687W 0 @ 3.10GHz with 64GB RAM running Microsoft Windows 8.1 Enterprise. This computer took about 1 hour and 32 minutes to complete the primality test using LLR. Naoki is a member of the Doshisha University team.

For more details, please see the official announcement.

2015-06-06: Primegrid Birthday Challenge starts June 12th, 18:00 UTC

It's PrimeGrid's Birthday!

And we're going to celebrate with, of course, a challenge!

From June 12th 18:00:00 UTC until June 15th 18:00:00 UTC we will have a 3 day challenge running the SoB/PSP/ESP Sieve.

For more information and questions regarding this challenge, please join us in this thread on the forums.

2015-05-11: PRPNet May Challenge

Top Gun Day is May 13th. Use as many Top Gun lines throughout the day as possible, wear aviator sunglasses and join us over at the Factorial prime search for the TOP GUN Challenge (May 13-27th). Should be a fun!

Discussion and more information can be found here: 2015 PRPNet May Challenge.

Good luck!

2015-05-11: PPS Mega Prime!

On 19 April 2015, 01:16:36 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

197*2^3477399+1

The prime is 1,046,804 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 109th overall.

The discovery was made by Tom Greer (tng*) of the United States using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 16GB RAM running Microsoft Windows 7 Ultimate. This computer took about 3 hours 5 minutes to complete the primality test using LLR. Tom is a member of the Sicituradastra. team.

The prime was verified on 19 April 2015, 03:32:00 UTC, by Naoki Yoshioka (oevrtaker@biomaterial) of Japan using an Intel(R) Xeon(R) CPU E5-2687W 0 @ 3.10GHz with 64GB RAM running Microsoft Windows 8.1 Enterprise. This computer took about 1 hour and 32 minutes to complete the primality test using LLR. Naoki is a member of the Doshisha University team.


For more details, please see the official announcement.

2015-05-01: GFN-Short CUDA tasks suspended

I have suspended the GFN-Short CUDA tasks for Nvidia GPUs. If you were previously using the GFN-Short CUDA app, please select the GFN-Short OpenCL app for Nvidia instead.

The CUDA app has a lower B limit than either the OpenCL or CPU apps, and we've reached the point where CUDA tasks might start failing.

GFN-WR and PPS-Sieve CUDA apps are not affected by this change.

2015-04-18: World Expo Challenge starts April 23, 18:00 UTC

On April 23rd, 2015 at 18:00 UTC the World Expo Challenge will start and last for 8 days.

Please do join in the fun and should you be looking for more information, questions, banter and general merry making please join us in this thread on the forums.

2015-04-13: 321 Mega Prime! (2015 Edition)

On 13 March 2015, 19:55:59 UTC, PrimeGrid?s 321 Prime Search project found the mega prime:

3*2^11731850-1

The prime is 3,531,640 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 12th overall. This is the largest known 321 mega prime and the largest prime found to date at PrimeGrid!

The discovery was made by Karsten Klopffleisch (KarstenK) of Germany using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 16 GB RAM running Linux. This computer took about 18 hours and 33 minutes to complete the primality test using LLR.

The prime was verified on 18 March 2015 18:17:44 UTC, by Thomas Gbenro (dagee) of Germany using an Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 12 hours and 16 minutes to complete the primality test using LLR. Thomas is a member of the BOINC@Frankfurt Team.

For more details, please see the official announcement.

2015-04-03: PRPNet April Challenge

Easter Egg Hunt

Join us over at the Wall-Sun-Sun prime search from the 3rd till 10th of April for an Easter Egg Hunt.

Winners will be judged in the following categories:
? Most Near Finds (most Eggs found)
? Nearest Find (prettiest Egg)
? Highest Score (most searching)

Discussion and more information can be found here: 2015 PRPNet April Challenge.

Good luck!

2015-03-31: 27 Mega Prime!

On 9 March 2015, 17:49:18, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search (k=27 sister project), has found the mega prime:

27*2^5213635+1

The prime is 1,569,463 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 38th overall.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel(R) Xeon(R) CPU E5-2648L 0 @ 1.80GHz Processor with 64GB RAM, running Microsoft Windows 7 Ultimate. This computer took about 5 hours and 5 minutes to complete the primality test using LLR. Hiroyuki is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2015-03-04: Solar Eclipse Challenge starts March 15th 2015, 07:41 UTC

To celebrate the beauty and significance of this natural phenomenon to certain cultures, we're hosting a challenge on the SR5 subproject in the run up to the start of it. The challenges starts on March 15th 2015, at 07:41 UTC .

Please do join in the fun and should you be looking for more information, questions, banter and general merry making please join us in this thread on the forums.

2015-03-04: Solar Eclipse Challenge starts March 20th 2015, 07:41 UTC

To celebrate the beauty and significance of this natural phenomenon to certain cultures, we're hosting a challenge on the SR5 subproject. The start of both events will happen at the same time: 07:41 UTC on March 20th, 2015.

Please do join in the fun and should you be looking for more information, questions, banter and general merry making please join us in this thread on the forums.

2015-03-03: Discussion about 3 and 4 day deadlines

We have a number of short sub-projects, most of which have 3 day deadlines. One (TRP-Sieve) has a 4 day deadline. They should all be 3 days. Or they should all be 4 days. Have an opinion? Talk about it here: http://www.primegrid.com/forum_thread.php?id=6166.

2015-03-02: TRP-Sieve deadline to be reduced to 3 days

For more details or to comment, please see this forum thread: http://www.primegrid.com/forum_thread.php?id=6166.

2015-03-01: PRPNet March Challenge

Binary Cyclops Challenge

27 and 2015 are binary cyclops numbers and to celebrate we're running a PRPNet challenge at the 27 prime search project from March 6th 18:00 UTC until March 13th 18:00 UTC.
We'll be taking the 27 prime search project to 5M and beyond.
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.
To take part, you have to activate the following line in prpclient.ini:
server=27:100:1:prpnet.primegrid.com:12006
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2015 PRPNet March Challenge.

Good luck!

2015-02-22: Fermat Divisor!

On 13 February 2015 16:10:21 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor:

267*2^2662090+1 Divides F(2662088)

The prime is 801,372 digits long and entered Chris Caldwell's The Largest Known Primes Database ranked 3rd for prime Fermat divisors and 212th overall.

The discovery was made by Jay Parangalan (stellarfirefly) of the United States using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 32GB RAM running Microsoft Windows 7 Ultimate. This computer took about 2 hours 23 minutes to complete the primality test using LLR.

The prime was verified on 14 February 2015 by user Lee of the United States using an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 16GB RAM running Microsoft Windows 8.1 Professional. This computer took about 2 hours 1 minute to complete the primality test using LLR.

For more details, please see the official announcement.

2015-02-22: Another PPS Mega Prime!

On 14 February 2015, 18:24:10 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

113*2^3437145+1

The prime is 1,034,686 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 108th overall.

The discovery was made by Evelyn Chew (Crackenback) of Australia using an Intel(R) Pentium(R) CPU G3220 @ 3.00GHz with 4GB RAM running Microsoft Windows 7 Enterprise. This computer took about 3 hours 1 minute to complete the primality test using LLR. Evelyn is a member of the BOINC@AUSTRALIA team.

The prime was verified on 15 February 2015, 10:52:20 UTC, by Grzegorz Roman Granowski (For the Universe ( Apaszko-Kaszkiety)) of Poland using an Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz with 16GB RAM running Microsoft Windows 7 Professional. This computer took about 7 hours and 45 minutes to complete the primality test using LLR. Grzegorz is a member of the BOINC@Poland team.


For more details, please see the official announcement.

2015-02-11: New GFN and GFN-WR 3.07 (3.2.6) apps released

I just put a new version of all builds of the Genefer app into production on the BOINC server. This is BOINC app version 3.07, and corresponds to Genefer 3.2.6.

Its primary change is to correct a potential memory corruption problem that could occur when resuming from a checkpoint. This only has been shown to occur under specific testing conditions and we don't believe it was ever a problem in production, and we're not worried about the validity of past results. (It would have been caught by the normal double checking if it did occur.)

There may also be a small speed increase in some of the builds,

If you encounter any problems, please report them in the Genefer 3.2.6 testing thread. Thank you!

2015-02-03: PPS MEGA Prime of the Month!

On 1 February 2015, 16:49:00 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

159*2^3425766+1

The prime is 1,031,261 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 107th overall.

The discovery was made by Evelyn Chew (Crackenback) of Australia using an Intel(R) Core(TM) i5-4670 CPU @ 3.40GHz with 8GB RAM running Microsoft Windows 7 Enterprise. This computer took about 1 hour 31 minutes to complete the primality test using LLR. Evelyn is a member of the BOINC@AUSTRALIA team.

The prime was verified on 1 February 2015, 19:11:39 UTC, by Matt Jurach (mattozan) of the United States using an Intel(R) Core(TM) i7-4500U CPU @ 1.80GHz with 16GB RAM running Microsoft Windows 8.1. This computer took about 6 hours and 9 minutes to complete the primality test using LLR. Matt is a member of the Aggie The Pew team.


For more details, please see the official announcement.

2015-01-31: Tour de Primes 2015

PrimeGrid is pleased to be offering a little side challenge in February: the 7th annual Tour de Primes. You can run almost any subproject you like, be it via our BOINC server or our PRPNet server. Unlike the regular challenges, this one will not give you challenge points for the challenge leader board but you can win a unique badge.

For more information, questions and general good fun please join us on our forums in this thread.

2015-01-18: PRPNet January Challenge

Wieferich Water-carrier Challenge

Announced is a PRPNet challenge at the Wieferich prime search project from January 20th 09:37:19 UTC until 27th 09:37:19 UTC.
Leading edge of the WFS prime search now up to 3.4e17. Goal will be to get to 4.0e17.
More about Wieferich prime search can be found here. News and infos about the PRPNet client can be found here.
To take part, you have to activate the following lines in prpclient.ini:

server=WIEFERICH:100:1:prpnet.primegrid.com:13000
Stats will be available at the well known place here.
All previous PRPNet challenge stats can be found here.
Discussion and more information can be found here: 2015 PRPNet January Challenge.

Good luck!

2015-01-17: ESP Mega Prime!

On 6 January 2015, 11:24:47 UTC, PrimeGrid?s Extended Sierpinski Problem Prime Search found the Mega Prime:

161041*2^7107964+1

The prime is 2,139,716 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd overall. It eliminates k=161401; 11 k's remain in the Extended Sierpinski Problem.

The discovery was made by Martin Vanc (vmv) of the Czech Republic using an Intel(R) Core(TM) i5-4440 CPU @ 3.10GHz with 4GB RAM running Microsoft Windows 7. This computer took about 18 hours 9 minutes to complete the primality test using LLR. Martin is a member of the Czech National Team.

The prime was verified on 7 January 2015, 00:34:44 UTC, by Stefan Hofacker (shofacker) of Germany using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 32GB RAM running Microsoft Windows 7 Professional. This computer took about 22 hours and 19 minutes to complete the primality test using LLR. Stefan is a member of the SETI.Germany team.


For more details, please see the official announcement.

2015-01-16: Another PPS Mega Prime!

On 7 January 2015, 1:57:29 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

245*2^3411973+1

The prime is 1,027,109 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 107th overall.

The discovery was made by Rick Channing (Rick) of the United States using an Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz with 4GB RAM running Microsoft Windows 7 Home Premium. This computer took about 3 hour 38 minutes to complete the primality test using LLR. Rick is a member of the SETI.USA team.

The prime was verified on 7 January 2015, 11:33:36 UTC, by John Christy (John Christy) of the United States using an Intel(R) Xeon(R) CPU E31220 @ 3.10GHz with 8GB RAM running Linux. This computer took about 1 hour and 35 minutes to complete the primality test using LLR. John is a member of the USA team.


For more details, please see the official announcement.

2015-01-14: PPS MEGA Prime Found!

On 6 January 2015, 18:51:43 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

177*2^3411847+1

The prime is 1,027,071 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 107th overall.

The discovery was made by William Darney (William J. Darney (G46VW)) of the United States using an AMD Phenom(tm) II X6 1090T with 16GB RAM running Microsoft Windows 7 Professional. This computer took about 3 hour 42 minutes to complete the primality test using LLR. William is a member of the LinusTechTips_Team team.

The prime was verified on 6 January 2015, 23:32:13 UTC, by Michael Becker (Nasicus) of Germany using an Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz with 32 GB RAM running Microsoft Windows Server 2012 R2 Standard Edition. This computer took about 2 hours and 49 minutes to complete the primality test using LLR. Michael is a member of the Crunchers@Freiburg team.


For more details, please see the official announcement.

2015-01-10: End-0f-Challenge Instructions

With a little under 1 day left on the clock, it's time for the usual end of challenge reminder :)

At the Conclusion of the Challenge

We would prefer users "moving on" to finish those tasks they have downloaded, if not then please ABORT the WU's instead of DETACHING, RESETTING, or PAUSING.

ABORTING WU's allows them to be recycled immediately; thus a much faster "clean up" to the end of a Challenge. DETACHING, RESETTING, and PAUSING WU's causes them to remain in limbo until they EXPIRE. Therefore, we must wait until WU's expire to send them out to be completed.

This is doubly important during this challenge because of the very long deadlines on the SoB tasks, which are either 45 or 60 days. If you do not COMPLETE or ABORT the tasks, we have to wait 6 or 8 weeks until the tasks can be re-issued! Thanks in advance for your cooperation.

2015-01-02: Exact BOINC task timing

If you have a relatively new BOINC client, you may notice that BOINC suddenly got better at estimating how much longer your PrimeGrid tasks will take to finish. BOINC will now ignore its internal estimate of how long the task should take and will rely only on the elapsed time divided by the percentage completed (i.e., what we always tell you to do if you want a good estimate.)

For this to work, you need (I believe) BOINC client 7.3.18 or later. The 7.2.xx clients that many still use do not support this feature.

Please note that this only affects the "Remaining (estimated)" display for tasks that have already started. Tasks that have not started are not affected and may still show erroneous (or wildly erroneous) times. It also won't have any affect on BOINC deciding to download too much or too little work because its time estimates are off. Only started tasks are affected by this new feature.

(The is the same functionality you can manually set yourself by using the tag in app_config.xml.)

2014-12-29: Year of the Sheep Challenge starts January 3 2015 18:00 UTC

To celebrate the start of a new year, PrimeGrid is hosting a challenge. The challenge will last for 8 days and run from January 3rd 2015, 18:00 UTC until January 11th 2015, 18:00 UTC.

This will be the first Multi Project Challenge (MPC), which means work units from multiple eligible projects, which are downloaded and completed during the challenge will count towards your challenge score. The eligible projects are: Seventeen-or-Bust (LLR), Prime Sierpinski Problem (LLR) and Extended Sierpinski Problem (LLR). Note that it's just the LLR's, and not the sieve!

For more information, questions and chit chat concerning this challenge, please join us in this thread. And as always we hope to see you there and feel free to spread the word.

2014-12-23: Dec 23 BOINC server problems

UPDATE 16:38 UTC: Everything is back up, and we have a suspected culprit process in mind as the root cause. (It's part of the challenge processing.) We'll keep an eye on it and make adjustments to keep this from happening in the future.

------

UPDATE 15:39 UTC: We've taken the BOINC server down and are currently optimizing the database tables. We may not need to take the entire database down, but some tables will be locked while they're optimized. This may impact certain website operations temporarily, including the forums.

----------

UPDATE 13:44 UTC: We're letting the transitioner catch up, which should complete in about 90 minutes. At that time, we're going to take BOINC down, and then take the database offline for maintenance. Most of the website will not operate while the database is down. It is unknown how long that will take, but my best guess is an hour or two.

Most background processing, including the validator and most statistics are suspended.

----------

As of approximately 12:45 UTC on Dec 23, 2014, we are investigating a problem with the PrimeGrid BOINC server.

If this requires taking down the database, most website functions won't work (including these forums), but PRPNet will be unaffected.

BOINC is working intermittently -- if your BOINC client is having trouble getting work or returning results, just let it keep trying.

More information will be forthcoming as it become available.

2014-12-13: PPS MEGA Prime Found!

On 1 December 2014, 8:02:57 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

255*2^3395661+1

The prime is 1,022,199 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 107th overall.

The discovery was made by John Christy (John Christy) of the United States using an Intel(R) Xeon(R) CPU E31220 @ 3.10GHz with 8GB RAM running Linux. This computer took about 1 hour 27 minutes to complete the primality test using LLR. John is a member of the USA team.

The prime was verified on 3 December 2014, 21:47:43 UTC, by Scott Bedenbaugh (PixelSmasher8) of the United States using an AMD FX(tm)-8320 Eight-Core Processor with 16 GB RAM running Microsoft Windows 7 Professional. This computer took about 4 hours and 54 minutes to complete the primality test using LLR. Scott is a member of the SEACOAST -- SouthEAst COalition of Alien Signal Trackers team.


For more details, please see the official announcement.

2014-12-09: 321 Mega Prime!

On 22 November 2014, 14:46:02 UTC, PrimeGrid?s 321 Prime Search project found the mega prime:

3*2^11484018-1

The prime is 3,457,035 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 12th overall. This is the largest known 321 mega prime and the largest prime found to date at PrimeGrid!

The discovery was made by Serhiy Gushchak (Sergyg) of the Ukraine using an Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz with 12 GB RAM running Microsoft Windows 7 Ultimate. This computer took about 27 hours and 2 minutes to complete the primality test using LLR. Serhiy is a member of the Ukraine Team.

The prime was verified on 24 November 2014 11:24:03 UTC, by Thomas Schulze Curly of Germany using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 16 GB RAM running Microsoft Windows 7 Professional. This computer took about 32 hours and 56 minutes to complete the primality test using LLR. Thomas is a member of the BOINCStats Team.

For more details, please see the official announcement.

2014-12-09: PRPNet December Challenge

Foundations of Computational Mathematics Challenge

Announced is a PRPNet challenge at the 27 & 121 prime search projects from the 9th till 16th of December.

Leading edge of the 27 prime search now up to 4,754,362 on both the plus and minus sides.
Leading edge of the 121 prime search now up to 6,107,197 on both the plus and minus sides.

If you haven't tried PRPNet now's the time to give it a try.
More about the 27121 prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=27:50:1:prpnet.primegrid.com:12006
server=121:50:1:prpnet.primegrid.com:12001
Note the 50 here sets the % of WU sent from the server, set to what %'s you prefer but must sum to 100.

All previous PRPNet challenge stats can be found here.

Discussion and more information can be found here: 2014 PRPNet December Challenge.

Good luck!

2014-12-08: Winter Solstice Challenge starts Dec 18th 23:03 UTC

Dear all,

The end of the year is drawing closer and this is traditionally marked with the winter solstice challenge here at PrimeGrid. As in previous years we would like to invite everyone to join us in this celebration of tidings of comfort and joy by sieving away for the Proth Prime Search. The challenge will start on Dec 18 23:03 UTC and last for 72 hours.

For more information, cheery banter and general merrymaking please join us on the discussion board.

We hope to see you there and please do spread the word :)

2014-11-28: Saint Nicholas' Challenge starts December 5th 00:00 UTC

To celebrate the great tradition of Sinterklaas (a.k.a. Saint Nicholas, a.k.a. Saint Nick a.k.a. Santa Claus) which takes place on December 5th in the Netherlands, PrimeGrid is offering 24 hour challenge on December 5th on the Sophie Germain Prime Search subproject.

Note that the starting time is midnight (i.e., the very beginning of December 5th), rather than the usual 18:00:00.

For more information, banter and statistics please do join us on the forums.

2014-11-06: Leonids Challenge starts November 19th 18:00 UTC

November traditionally sees the skies lit up with falling stars a couple of nights during the Leonids meteor shower. Similarly on here on PrimeGrid November is the time for a challenge on our 321 LLR sub-project. This year the challenge will take place between November 19th 18:00 UTC and November 24th 18:00 UTC.

We hope that many of you will join us in this challenge and as always you can visit our forum for more useful information, cheery banter and some free roaming cows, rats, dogs, pigs and just regular users.

Please do spread the word and invite anyone to join us.

2014-10-31: PRPNet November Challenge

Factorial & Primorial Combinatorial Challenge

Announced is a PRPNet challenge at the Factorial & Primorial prime search projects from the 1st till 15th of November.

Leading edge of the Factorial prime search now up to 165,784 on both the plus and minus side.
Leading edge of the Primorial prime search now up to 1,803,563 on both the plus and minus side.

If you haven't tried PRPNet now's the time to give it a try.
More about the Factorial prime search can be found here. More about the Primorial prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=FPS:50:1:prpnet.primegrid.com:12002
server=PRS:50:1:prpnet.primegrid.com:12008
Note the 50 here sets the % of WU sent from the server. Set to what %'s you prefer but must sum to 100.

Stats will be available at the well known place here.

All previous PRPNet challenge stats can be found here.

Discussion and more information can be found here: 2014 PRPNet November Challenge.

Good luck!

2014-10-28: SR5 Mega Prime!

On 18 October 2014, 6:18:40 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=109208 by finding the mega prime:

109208*5^1816285+1

The prime is 1,269,534 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 59th overall. This is the largest known base 5 mega prime. 37 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM)2 Quad CPU Q6700 @ 2.66GHz with 8GB RAM running Windows 7 Enterprise. This computer took about 11 hours and 3 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

The prime was verified on 21 October 2014, 6:19:48 UTC, by Tod Slakans (NeoMetal*) of the United States using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 8GB RAM running Microsoft Windows 7 Home Premium. This computer took about 3 hours and 11 minutes to complete the primality test using LLR. Tod is a member of the Sicituradastra. team.

For more details, please see the official announcement.

2014-10-19: PPS MEGA Prime Found!

On 23 September 2014, 17:30:36 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

179*2^3371145+1

The prime is 1,014,819 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 105th overall.

The discovery was made by John Christy of the United States using an Intel(R) Xeon(R) CPU E31220 @ 3.10GHz with 8GB RAM running Linux. This computer took about 1 hour 27 minutes to complete the primality test using LLR. John is a member of the USA team.

The prime was verified on 23 September 2014, 21:47:43 UTC, by Patrick Martin (ptube974) of the United States using an Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz with 8 GB RAM running Linux. This computer took about 4 hours and 22 minutes to complete the primality test using LLR. Patrick is a member of the Overclock.net team.

The prime was reported to The Largest Known Primes Database by Patrick following a period of non-reporting by the discoverer .

For more details, please see the official announcement.

2014-10-17: Another TRP Prime!

On 4 October 2014, 22:32:24 UTC, PrimeGrid?s The Riesel Problem project eliminated k=502573 by finding the mega prime:

502573*2^7181987-1

The prime is 2,162,000 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 20th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 14th elimination. 50 k's now remain.

The discovery was made by Denis Iakovlev (Goliaf-RS) of Russia using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8 GB RAM running Windows 7 Professional. This computer took about 19 hours and 40 minutes to complete the primality test using LLR. Denis is a member of the Russia Team.

The prime was verified on 5 October 2014, 11:48:03 UTC, by Russell Mathers (Russ) of the United Kingdom using an Intel(R) Core(TM) i7-3960X CPU @ 3.30GHz with 16 GB RAM running Microsoft Windows 7 Professional. This computer took about 18 hours and 46 minutes to complete the primality test using LLR.


For more details, please see the official announcement.

2014-10-14: TRP Mega Prime!

On 2 October 2014, 3:02:44 UTC, PrimeGrid?s The Riesel Problem project eliminated k=402539 by finding the mega prime:

402539*2^7173024-1

The prime is 2,159,301 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 20th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 13th elimination. 51 k's now remain.

The discovery was made by Walter Darimont (Walter Darimont) of Belgium using an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 4 GB RAM running Linux. This computer took about 11 hours and 10 minutes to complete the primality test using LLR. Walter is a member of the Aggie the Pew Team.

The prime was verified on 2 October 2014, 9:51:42 UTC, by Tom Greer (tng*) of the United States using an Intel(R) Xeon(R) CPU E5520 @ 2.27GHz with 24 GB RAM running Microsoft Windows 7 Professional. This computer took about 25 hours and 35 minutes to complete the primality test using LLR. Tom is a member of the Sicituradastra. Team.


For more details, please see the official announcement.

2014-10-12: SR5 Mega Prime!

On 21 September 2014, 18:43:31 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=325918 by finding the mega prime:

325918*5^1803339-1

The prime is 1,260,486 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 58th overall. This is the largest known base 5 mega prime. 79 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Jรถrg Meili (meilijo) of Switzerland using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM running Microsoft Windows 7 Home Premium. This computer took about 20 hours and 51 minutes to complete the primality test using LLR. Jรถrg is a member of the Aggie the Pew team.

The prime was verified on 1 October 2014, 12:57:59 UTC by Yegor Ryabchikov (Yegor001) of Russia using an Intel(R) Core(TM) i5 CPU 760 @ 2.80GHz with 2GB RAM running Microsoft Windows 7 Home Basic. This computer took about 133 hours 16 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-10-07: PRPNet October Challenge

Wall-Sun-Sun PRPNet Challenge

To celebrate the Total Lunar Eclipse on the 8th of October Project Staging Area is holding a 12 day challenge on the Wall-Sun-Sun prime search, running until the 20th of October.
We're currently at 5.3e16. Goal will be to get to 5.6e16.

If you haven't tried PRPNet now's the time to give it a try.
More about the Wall-Sun-Sun prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=WALLSUNSUN:100:2:prpnet.primegrid.com:13001
Stats will be available at the well known place here.

Discussion and more information can be found here: 2014 PRPNet October Challenge.

Good luck!

2014-09-30: AVG interference with BOINC

It seems that AVG has been randomly flagging some of our executables as having an identity theft trojan, and removing them from the BOINC directory. It only happens occasionally and is likely a bug in AVG. The executables themselves are fine and pose no threat.

If you use AVG, I *strongly* recommend configuring AVG to ignore the C:\ProgramData\BOINC folder, and also disable identify protection. You can't tell the identity protection system to ignore a folder, so you have to completely disable it.

Or switch to a different anti-virus product.

This can be discussed here.

2014-09-29: PrimeGrid is back!

We had a bit of an exciting weekend, and what was originally a planned maintenance downtime of a few hours turned into a two day "rebuild and upgrade everything" challenge.

We're back up now, and once the DNS name for the new server propagates throughout the Internet everyone should be able to connect again.

For more information, please see this discussion.

2014-09-27: Primegrid downtime starting Sunday, September 28th

Sometime on Sunday, September 28th we expect to take both the BOINC and PRPNet servers down for maintenance.

This is expected to happen sometime within a 24 hour period staring as early as 11:00 UTC. We expect the servers to be back up no later than 11:00 UTC on Monday.

The host machines that our virtual servers are running on are going to be rebooted sometime during that timeframe, and we want the database to be stopped when that occurs to avoid any chance of corrupting the database.

We will try to keep the downtime as short as possible, but since we don't know exactly when the servers will be rebooted, we may need to keep the servers shut down for a large part of the Window.

You may wish to increase your queue of tasks to 24 hours to make sure you don't run out of work.

We apologize for any inconvenience this may cause.

For questions, updates, and more information, please see this thread.

2014-09-24: World Animal Day Challenge starts October 4th, 18:00 UTC

People have always had an interesting relationship with animals. We hunt them for food, we keep livestock for food too but we also use them for labor and keep them as pets and love them like family. In honor of this relationship there is a special day, World Animal Day. To mark this day, PrimeGrid invites every one to participate in the challenge starting at 18:00 utc on October 4th, 2014 it will run for five days until October 9th, 2014, 18:00 UTC

For questions, banter, information you can go to this thread in our forums.

Please do spread the word and join the fun!

2014-09-12: SR5 Mega Prime!

On 17 August 2014, 13:00:59 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=133778 by finding the mega prime:

133778*5^1785689+1

The prime is 1,248,149 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 56th overall. This is the largest known base 5 mega prime. 38 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Guo Hua Miao (????) of China using an Intel Xeon(R) CPU E5-4617 @ 2.90GHz with 504GB RAM running Linux. This computer took about 27 hours and 9 minutes to complete the primality test using LLR. Guo is a member of the Team China team.

For more details, please see the official announcement.

2014-09-06: PRPNet server upgraded!

The new and improved PRPNet server is now online.

Information and discussion can be found here.

2014-09-05: PRPNet server being upgraded

We're taking the PRPNet server offline for a few hours to upgrade the hardware.

More information and discussion can be found here.

2014-09-05: 27 Mega Prime!

On 22 August 2014, 4:33:59 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search (k=27 sister project), has found the mega prime: 27*2^4583717-1

The prime is 1,379,838 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 48th overall.

The discovery was made by Hans Joachim Bรถhm (SEARCHER) of Germany using an Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz Processor with 4GB RAM, running Microsoft Windows 7 Ultimate. This computer took just over 15 hours 24 minutes to complete the primality test using LLR. Hans is a member of the SETI.Germany team.

For more details, please see the official announcement.

2014-08-29: PRPNet September Challenge

Wieferich PRPNet Challenge

A one month challenge on the Wieferich prime search is being held during the month of September.
We're currently at 1.54e17. Goal will be to get to 2.0e17.

If you haven't tried PRPNet now's the time to give it a try.
More about Wieferich prime search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=WIEFERICH:100:1:prpnet.primegrid.com:13000
Discussion and more information can be found here: 2014 PRPNet September Challenge.

Good luck!

2014-08-19: PPS-Sieve ATI apps and GFN MAC ATI apps turned back on.

A little late on the announcement, but we've fixed and corrected two apps that had to be taken offline earlier this year.

The ATI/AMD version of the PPS-Sieve app was put back online a couple of days ago. More details can be found in this thread.

The GFN (short and WR) ATI/AMD Mac apps were put back into service last month. More details can be found here.

We are very grateful for the volunteer developers, builders, and testers who put so much effort into fixing those apps. Thanks!

2014-08-08: New MEGA prime and World Record Fermat Divisor!

On 25 July 2014, 8:47:48 UTC, PrimeGrid?s Mega Prime Search found a world record prime Fermat divisor:

193*2^3329782+1 Divides F(3329780)

The prime is 1,002,367 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for prime Fermat divisors and 98th overall. It is also a new record for "weighted" prime Fermat divisors.

The discovery was made by Raymond Ottusch (RaymondFO*) of the United States using an Intel Core i7-3930K CPU @ 3.20GHz with 12 GB RAM running Microsoft Windows 7 Professional. This computer took about 1 hour 11 minutes to complete the primality test using LLR. Raymond is a member of the Sicituradastra. team.

The prime was verified on 28 Jul 2014, 5:02:21 UTC by John Christy (John Christy) of the United States using an Intel Xeon CPU E31220 @ 3.10GHz with 8 GB RAM running Linux. This computer took about 1 hour and 24 minutes to complete the primality test using LLR. John is a member of the USA team.

For more details, please see the official announcement.

2014-08-07: New MEGA prime found!

On 24 July 2014, 3:59:36 UTC, PrimeGrid?s Mega Prime Search found the Mega Prime:

129*2^3328805+1

The prime is 1,002,073 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 98th overall.

The discovery was made by Eric Clifton (Grandpa) of the United States using an Intel Core i7-2700K CPU @ 3.50GHz with 16GB RAM running Microsoft Windows 7 Professional. This computer took about 46 minutes 7 seconds to complete the primality test using LLR. Eric is a member of the [H]ard|OCP team.

In addition to being verified internally, the prime was also verified on 27 July 2014, 3:34:11 UTC, by Vladislav Ketamino (ThrasherX-17) of the Ukraine using a Genuine Intel CPU @ 1.60GHz with 8 GB RAM running Microsoft Windows 7 Ultimate. This computer took about 2 hours and 18 minutes to complete the primality test using LLR. Vladislav is a member of the Keep The Fire Alive! team.

For more details, please see the official announcement.

2014-08-06: New SR5 Mega Prime!

On 23 July 2014, 5:52:51 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=24032 by finding the mega prime:

24032*5^1768249+1

The prime is 1,235,958 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 39 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Hiroyuki Okazaki (zunewantan) of Japan using an Intel Xeon CPU E31220 @ 3.10GHz with 4GB RAM running Microsoft Windows Server 2008. This computer took about 3 hours and 16 minutes to complete the primality test using LLR. Hiroyuki is a member of the Aggie The Pew team.

The prime was verified on 23 July 2014, 8:30:46 UTC, by Vincent Ollivier (MohMan) of Canada using an Intel Core i7-3770 CPU @ 3.40GHz with 8 GB RAM running Microsoft Windows 7 Professional. This computer took about 6 hours and 38 minutes to complete the primality test using LLR. Vincent is a member of the SUPINFO team.

For more details, please see the official announcement.

2014-08-06: 27 Mega Prime

On 17 July 2014, 2:36:47 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search (k=27 sister project), has found the mega prime: 27*2^4542344-1

The prime is 1,367,384 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 47th overall.

The discovery was made by Scott Brown (Scott Brown) of the United States using an AMD Phenom(tm) II X6 1055T Processor with 4GB RAM, running Microsoft Windows 7 Enterprise. . This computer took just over 8 hours 25 minutes to complete the primality test using LLR. Scott is a member of the Duke University Team.

For more details, please see the official announcement.

2014-08-05: Perseid Challenge starts 12 August 18:00

The night sky can offer some wonderful sights, like distant stars and planets, the milkyway but also meteor showers. The perseids are a prolific meteor shower associated with the comet Swift-Tuttle. To celebrate this wonderful sight, PrimeGrid is running a challenge on the Riesel Problem Sieve subproject. It will start on 12 august 2014 at 18:00 UTC and will run until 14 august 2014, 18:00 UTC.

We hope to welcome many of you in this fun challenge and if you have any questions or just want some banter, please do join us in this thread on our forums.

2014-07-27: Genefer 3.2.2 released

The latest version of Genefer, v. 3.2.2, has been released and is live for both short and World Record tasks. Some notable changes:

1) The OpenCl and CPU apps are significantly faster than the previous versions.

2) It is likely that the OpenCL app is now faster than the CUDA app on any Nvidia GPU, but especially on newer (Kepler or later, 6xx or newer) GPUs. On the app selection page, the OpenCL app now appears before the CUDA app. NOTE: On Nvidia cards, the OpenCL driver hogs a CPU core. If you have an Nvidia GPU, you may chose between the faster app (OpenCL) or that app that uses very little CPU (CUDA).

3) The CPU app now supports the FMA3 instructions on Intel Haswell CPUs, which makes them even faster.

4) The bug in the Mac ATI app has been fixed.

Please see this thread for more information and discussion.

2014-07-26: PRPNet August Challenge

Grand Cleanup Walk PRPNet Challenge

A seven day challenge on the GCW Prime Search is being held from 1st till 8th of August, starting and ending at 12:00 UTC.

The Generalized Cullen/Woodall Prime Search was originally only for base 13. Now it has extended to several bases.
Its currently searching for Generalized Cullen primes n*b^n + 1 for bases 41, 47, 49 and 53.

If you haven't tried PRPNet now's the time to give it a try.
More about the GCW Search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:

server=GCW:100:1:prpnet.primegrid.com:12004
Discussion and more information can be found here: 2014 PRPNet August Challenge.

Good luck!

2014-07-20: GFN n=262144 Sieve (re)Starting

We're (re)starting manual sieving on GFN n=262144. Please see this message for more information.

2014-07-18: Mega Prime Search Now Running on BOINC

We have moved the PRPNet MEGA project over to the BOINC server. To run PPS-Mega, just select the PPS-Mega (LLR) app in your PrimeGrid Preferences.

The PPS-Mega project is part of our Proth Prime Search (PPS) project. There's now three ranges of PPS tests:

PPSE: Currently around n=1.3M and about 400K digits
PPS: Currently around n=2.1M and about 650K digits
Mega: 3.322M
The PPS-Mega tasks take about an hour on the fastest computers (Intel Haswell CPUs). This project is ideal for finding mega primes. In all of history, only 97 mega primes have ever been found -- but PrrimeGrid has already found 17 so far this year.

Will you discover the next mega prime?

2014-07-16: New MEGA prime found!

On 4 July 2014 21:42:34 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime:

35*2^3587843+1

The prime is 1,080,050 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 69th overall.

The discovery was made by Peter Tibbott (TroubledBunny) of the United Kingdom using an Intel i5-3570K CPU @ 3.40GHz with 8GB RAM running Microsoft Windows 7 Professional. This computer took about 1 hour 24 minutes to complete the primality test using LLR. Peter is a member of the UK BOINC Team.

The prime was verified internally.

For more details, please see the official announcement.

2014-07-15: Another New SR5 Prime Found!

On 27 June 2014, 20:20:40 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=138172 by finding the mega prime:

138172*5^1714207-1

The prime is 1,198,185 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 80 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Walter Darimont (Walter Darimont) of Belgium using an Intel Core i7-3770 CPU @ 3.40GHz with 3.8GB RAM running Linux. This computer took about 18 hours and 25 minutes to complete the primality test using LLR. Walter is a member of the Aggie The Pew team.

The prime was verified on 28 June 2014 13:08:49 UTC, by Scott Brown (Scott Brown) of the United States using an Intel Core2 CPU 6600 @ 2.40GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 38 hours and 32 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2014-07-15: New SR5 Mega Prime Found!

On 19 June 2014, 3:36:34 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=22478 by finding the mega prime:

22478*5^1675150-1

The prime is 1,170,884 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 54th overall. This is the largest known base 5 mega prime. 81 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Guo Hua Miao (????) of China using an Intel Xeon CPU E5-4617 @ 2.90GHz with 516GB RAM running Linux. This computer took about 25 hours and 24 minutes to complete the primality test using LLR. ???? is a member of Team China.

The prime was verified internally.

For more details, please see the official announcement.

2014-06-30: And Another New MEGA prime found!

On 10 June 2014 20:37:03 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime:

35*2^3570777+1

The prime is 1,074,913 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 66th overall.

The discovery was made by Robert Lacroix (composite) of Canada using an Intel(R) Xeon E5-2697 @ 2.7 GHz with 64GB RAM running Linux. This computer took about 1 hour 40 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-06-30: New MEGA prime found!

On 10 June 2014 5:22:14 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime:

33*2^3570132+1

The prime is 1,074,719 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 66th overall.

The discovery was made by Fabrice Le Foulher (JackTheSkipper) of France using an Intel(R) Core(TM) i7-2600k CPU @ 3.40GHz with 10GB RAM running Windows 7 Home Premium. This computer took about 1 hour 45 minutes to complete the primality test using LLR. Fabrice is a member of the L'Alliance Francophone team.

For more details, please see the official announcement.

2014-06-29: New BOINC Sub-Project: ESP Sieve

We have re-opened the suspended PSP sieve to do new sieving work for ESP, and renamed it the Sierpinski (ESP/PSP/SoB) Sieve. The reopened sieve uses the same statistics and badges as the PSP sieve.

For many people, this is a chance to get a new badge, and for others it is an opportunity to improve upon their existing PSP Sieve badge.

For more information, or to discuss the ESP Sieve, please see this forum thread.

2014-06-23: Sovereign Challenge Starts June 25th @ 18:00

One June 25th, starting at 18:00:00 UTC, PrimeGrid is hosting the Sovereign Challenge, a 3 day SR5 challenge.

SR5 has been our most prolific mega-prime project so far this year, with 8 mega primes already found in the first six months of 2014. Come and participate in the challenge, and maybe you'll find the next mega prime!

For more information, or to participate in the discussion, please see this thread.

Good luck!

2014-06-16: PPS-Sieve ATI app turned off temporarily

We have temporarily turned off the ATI apps for PPS-Sieve. We're going to need help with building and testing the fixed app.

Please see this thread for more information.

2014-06-13: PRPNet June Challenge

Genefer Mini Challenge

A nine day Genefer challenge of the mini N=262144 size is being held from 13th till 22nd of June.

If you haven't tried PRPNet now's the time to give it a try.
Download the new 5.3.1 PRPNet with all new genefer using a faster 'Z-transform' for CPU and OpenCL tasks.
Get in quick before the tested "B" values head too high for these much faster transforms.
More about the Generalized Fermat Number Search can be found here. News and infos about the PRPNet client can be found here.

To take part, you have to activate the following lines in prpclient.ini:
server=GFN262144:100:1:prpnet.primegrid.com:11002
Discussion and more information can be found here: 2014 PRPNet June Challenge.

Best of luck!

2014-06-07: New BOINC Sub-Project: ESP

We've just opened up the ESP (Extended Sierpinski Problwm) project on BOINC. There's a brand new set of ESP badges, so feel free to come and help solve the Extended Sierpinski Problem and also fill out your set of badges!

For more information please see this forum, and feel free to ask questions or discuss ESP in this thread.

2014-05-31: Mac GFN ATI apps temporarily turned off

I've turned off the Mac ATI OpenCL GFN apps. They're not working, although the completely identical Mac OpenCL Nvidia app works fine. (It's the exact same binary.)

If you have a Mac with a double precision ATI GPU and would like to help us diagnose this problem, please let us know on this thread.

2014-05-30: New MEGA prime found!

On 6 May 2014 13:40:30 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime:

93*2^3544744+1

The prime is 1,067,077 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 69th overall.

The discovery was made by Micha? Gasewicz (Genn) of Poland using an Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz with 8GB RAM running Linux. This computer took about 1 hour 39 minutes to complete the primality test using LLR. Micha? is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2014-05-28: New GFN Apps

Version 3.2.0 of all flavors of the GFN and GFN-WR apps have been installed. No action is necessary on your part; you will automatically receive the correct app for your computer.

It is no longer necessary to manually select the correct CPU app (SSE2/SSE3/AVX). This version does not yet support Haswell/FMA3/AVX2, but that's coming in the near future.

For more information, or to discuss the new apps, please see this thread.

2014-05-28: Short Maintenance Period TODAY

Shortly after the end of the end of the "Race to the New Moon" challenge at 19:43:00 UTC today, I will be taking down the PrimeGrid BOINC server for maintenance. This is necessary to make some changes required by the next generation of GFN apps.

For more information, or to discuss the new apps, please see this thread.

2014-05-14: Race to the New Moon challenge starts on May 20th, 19:43 UTC

Following the lunar cycle, PrimeGrid is giving chase to the new moon which should appear later this month. To do so we're hosting a challenge on the Cullen LLR project, on which no challenge has been before. The challenge will start on May 20th, at 19:43 UTC and last 8 days.

We invite you all to participate and look forward to seeing you both on the forums and in the statistics.

2014-05-05: SR5 Double Check Starting

In roughly 24 hours time we are gong to start a full double check of prior SR5 work. Initially, tasks will be much shorter and will take about 1 minute on the fastest computers. I expect the double check will take about 2 months to complete.

For more information, or to leave a comment, please see this discussion thread.

2014-05-04: PRPNet May Challenge

Sierpinski Attack

Primegrid is looking for more crunchers for an attack on the Extended Sierpinski Problem (ESP).
This is the most undersearched base 2 conjecture at Primegrid with n currently at 4.6M.
Compare that to TRP currently searching 7-10M, PSP searching 14-17M and SoB searching 21-28M.

ESP has 12 odd composite k's left to prime between the first and second Sierpinski number.

If you haven't tried PRPNet now's the time to give it a try.
We're aiming to bridge the gap to Primegrid's other base 2 conjectures.
More about ESP prime search can be found here. News and info about the PRPNet client can be found here.

A PRPNet challenge is currently also being run on this port.
To take part, you have to activate the following lines in prpclient.ini:

server=ESP:100:1:prpnet.primegrid.com:13005
Discussion and more information can be found here: 2014 PRPNet May Challenge.

Best of luck!

2014-04-27: Yet another SR5 prime discovered!

On 25 April 2014, 21:06:16 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=326834 by finding the mega prime:

326834*5^1634978-1

The prime is 1,142,807 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 56th overall. This is the largest known base 5 mega prime. 82 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i5-2410M CPU @ 2.30GHz with 6GB RAM running Microsoft Windows 7 Home Premium. This computer took about 44 hours and 32 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

The prime was verified on 26 April 2014 15:50:21 UTC, by Alejandro Kurtz (Alejandro) of Spain using an Intel(R) Core(TM) i5-2500 CPU @ 3.30GHz with 5.5 GB RAM running Microsoft Windows 7 Professional. This computer took about 13 hours and 28 minutes to complete the primality test using LLR. Alejandro is a member of the CANAL@Boinc team.

For more details, please see the official announcement.

2014-04-26: Another New SR5 Prime Found!

On 9 April 2014, 18:33:30 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=207394 by finding the mega prime:

207394*5^1612573-1

The prime is 1,127,146 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 59th overall. This is the largest known base 5 mega prime. 83 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Honza Cholt (Honza) of the Czech Republic using an Intel(R) Xeon(R) CPU E5-2609 0 @ 2.40GHz with 12GB RAM running Microsoft Windows Server 2008. This computer took about 16 hours and 5 minutes to complete the primality test using LLR. Honza is a member of the BOINC.SK team.

For more details, please see the official announcement.

2014-04-26: PRPNet GFN ports reopened!

The four GFN ports on PRPNet have been reopened. You'll need to be using PRPNet 5.3.0, including both the new versions of prpclient and genefer, to run GFN.

Due to the potential for erroneous results having been previously returned, some of the GFN candidates on all four ports will be retested. Most of the restests are on the GFN65536 port.

(This post applies only to our PRPNet GFN projects. The BOINC GFN projects are not affected.)

2014-04-19: New SR5 Mega Prime Found!

On 9 April 2014, 9:13:42 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=104944 by finding the mega prime:

104944*5^1610735-1

The prime is 1,125,861 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 59th overall. This is the largest known base 5 mega prime. 84 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Brian Smith (Sherlock Holmes) of Germany using an Intel(R) Core(TM)2 Duo CPU T9800 @ 2.93GHz with 4GB RAM running Microsoft Windows 7 Professional. This computer took about 27 hours and 21 minutes to complete the primality test using LLR.

The prime was verified on 9 April 2014 15:47:16 UTC, by Dave Sunderland (DaveSun) of the United States using an Intel(R) Core(TM)2 Quad CPU Q9300 @ 2.50GHz with 4 GB RAM running Microsoft Windows XP Professional. This computer took about 30 hours and 46 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-04-18: FMA3 LLR going live on all LLR projects

Early Sunday, April 20th UTC (Saturday afternoon or evening in the western hemisphere) we are going to install the new FMA3 (aka AVX2) version of LLR on the remaining LLR projects.

Especially on Intel Haswell CPUs, but to some extent also on Ivy Bridge and Sandy Bridge CPUs, this new app is significantly faster. It also consumes more power, and generates more heat. Please make sure your computer is up to running the new app.

In general, expect the highest temperatures with shorter projects (PPSE, SGS, and PPS) while longer projects such as SoB and PSP will run slightly less hot.

Information and discussion about the new LLR app can be found in this thread.

2014-04-14: 48 hour NOTICE: FMA3 LLR going live.

Sometime during Thursday, April 17th (UTC) we are going to install the new FMA3 (aka AVX2) version of LLR on the PPS project, in preparation for the Shakespeare's Birthday Challenge that starts on Sunday.

Especially on Intel Haswell CPUs, but to some extent also on Ivy Bridge and Sandy Bridge CPUs, this new app is significantly faster. It also consumes more power, and generates more heat. Please make sure your computer is up to running the new app.

Information and discussion about the new LLR app can be found in this thread.

I expect to install the new app for all of the other LLR projects sometime after it goes live on PPS, depending on how well the PPS deployment goes.

2014-04-14: Shakespeare's Birthday Challenge 20 April 2014 16:16 UTC

In honour of one of the most famous playwrights and poets in English literature, PrimeGrid is hosting a challenge from 20 April 2014 16:16 UTC until 23 April 2014 16:16 UTC on the Proth Prime Search (not extended!) Project.

For more information, answers to questions and general banter please do feel free to join us in this thread on our forums.

2014-04-09: Badge threshold changes

For longer than I can remember, some of PrimeGrid's badges have required twice the credit as other badges. The reason for that difference long ago ceased to be relevant and so we have lowered the required credit for those badges to be the same as all the others. Therefore, you may have gone up a badge level in those projects. This change also applies retroactively to closed or suspended projects.

The affected projects are all the sieves, AP26, GFN, and PSA.

Discussion of this topic is in this thread.

2014-04-05: Another MEGA Prime Found

On 28 March 2014 21:32:37 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime: 51*2^3490971+1

The prime is 1,050,889 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 69th overall.

The discovery was made by Stefan Larsson (288larsson) of Sweden using an Intel(R) Core(TM) i7-4930K CPU @ 3.40GHz with 16GB RAM running Microsoft Windows 8.1. This computer took just over 1 hour 13 minutes to complete the primality test using LLR. Stefan is a member of the Sicturadastra team.

For more details, please see the official announcement.

2014-04-05: MEGA Prime Found

On 28 March 2014 19:57:24 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime: 87*2^3496188+1

The prime is 1,052,460 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 70th overall.

The discovery was made by Gary Craig (Gary Craig) of the United States using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 4GB RAM running Linux. This computer took just over 1 hour 11 minutes to complete the primality test using LLR. Gary is a member of the Aggie The Pew team.

For more details, please see the official announcement.

2014-03-26: Help Wanted!

We're looking for one or more people to help with organizing and creating content on our forums.

For more information please see this thread.

2014-03-24: World record SR5 prime discovered!

On 21 March 2014, 13:39:54 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=330286 by finding the mega prime:

330286*5^1584399-1

The prime is 1,107,453 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 57th overall. This is the largest known base 5 mega prime. 85 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz with 4GB RAM running Microsoft Windows 7 Enterprise. This computer took about 35 hours and 55 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

The prime was verified on 23 March 2014 10:55:21 UTC, by Baneus of Germany using an AuthenticAMD Quad-Core AMD Opteron(tm) Processor 2356 with 64 GB RAM running Linux. This computer took about 73 hours and 11 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-03-23: we will bring it to an end ... MEGA Prime Search at PRPNet

Calling All Crunchers

The MEGA Prime Search is looking for more crunchers to help it finish.
The search will be wrapped up once the current remaining ~147 K WU's are complete.

Donate you computing power to this sub-project which is searching for a Mega Prime (at least one million digits). Work is currently at n=3,470,000 for 12

2014-03-10: Android Support Temporarily Disabled

The Android TRP-Sieve application has been disabled while we investigate a problem with this build of the sieve program.

I do not yet have an ETA for when a fix will become available. If you're currently running a task (or tasks) on Android you can complete and return them. However, no new tasks will be sent to Android devices until this problem is resolved.

I apologize for any inconvienence this may cause.

Discussion about the Android app is ongoing in this thread.

2014-03-07: False Google malware alert

Earlier today Google's Chrome browser started blocking access to some forum posts on PrimeGrid's website. Most importantly, there is no malware at PrimeGrid and it is 100% safe to access our website.

What happened is not specific to PrimeGrid, and in fact isn't specific to BOINC. This false report likely affected numerous tech forums across the entire Internet.

Many people use CPU-Z to monitor their computers, and also use their "validation" system to register and show off their computers. The website used by CPU-Z for this validation is "valid [dot] canardpc [dot] com" and that's the website that Google thinks is malicious. (I don't actually know if it is or not. I suspect it's fine.)

Because many people put a link to their CPU-Z validations in either their signatures or in posts, any forum webpage with such a link now gets blocked by Google as malicious.

Just to be perfectly clear, even if CPU-Z's website WAS malicious, merely viewing the PrimeGrid forum pages would not pose any risk.

While researching this problem on the web, I discovered that this is not the first time CPU-Z has been erroneously flagged by Google as being malicious. It's therefore reasonable to expect that it also won't be the last. In order to prevent this from happening in the future, effective immediately links or references to the CPU-Z validation site are prohibited in both forum posts and in signatures. The server will automatically remove posts or signatures that reference valid [dot] canardpc [dot] com. Four signatures and a handful of posts had to be removed.

2014-03-03: Consumer-grade UPSs and new computers

If you use a consumer grade UPS (Uninterruptable Power Supply) to keep your computer running during momentary power glitches or short outages, you should probably read this thread:

Oops! Lesson learned about UPS and active PFC power supplies

(Discussion on this topic should be directed to that thread.)

In short, most of the inexpensive UPSs you would buy for your home are incompatible with newer computer power supplies because the power supply uses something called "Active PFC". If the UPS switches to battery power, the computer may shut off. In the worst case scenario, the UPS, the computer power supply, or other components of the computer may be damaged.

The problem is that most inexpensive UPSs don't produce a true sine wave output, and that messes up the active PFC power supplies.

Business grade UPSs (such as APC's "Smart-UPS" line) produce pure sine wave outputs and work fine with new power supplies, but those start at around $300. The only consumer grade UPSs with true sine wave outputs that I'm aware of are from Cyberpower. They're a little more expensive, but much less than the business grade UPSs.

If you have a computer with a power supply that has active PFC, or if you might ever get one in the future, you don't want to use a UPS with "stepped" or "simulated" sine wave output. At best, the computer will shut off. At worst, you'll be buying new computer parts. Keep in mind that as time goes on, more and more power supplies will be using active PFC. It's a "green" technology, is good for the power grids, and is mandated by regulation in some jurisdictions, notably the EU.

2014-02-24: Double Top Secret Mystery Challenge starts March 1st 2014, 18:00 UTC

After 4 year long hiatus, PrimeGrid is once more offering a challenge on the Prime Sierpinski Problem subproject. The challenge will last 15 days and runs from March 1st, 2014 18:00 UTC to March 16th, 2014 18:00 UTC.

For more information, assistance and cheery banter please do join us on the forums in this thread

2014-02-15: GFN PRPNet ports temporarily shut down

We are investigating a software issue with the four GFN PRPNet ports which is affecting the quality of the results.

Until this issue is resolved, no new work will be sent out on any of the GFN ports.

Obviously, if you wish to do so, please feel free to crunch on the BOINC GFN-Short or GFN-WR projects instead while the problem with the PRPNet ports is being corrected.

If you happen to be using geneferocl 3.2.0-0beta with app_info on BOINC, please stop using the beta app. In at least some tests it's producing incorrect results and will fail validation.

For more information, please see this thread.

2014-02-11: Fix for running new AMD GPUs (r9 280x, etc.)

If you've been having trouble getting BOINC tasks on Primegrid or other projects for your new AMD r9 280x and similar GPUs, there may be a fix.

Please see this discussion for details.

In short, you'll need to upgrade to at least version 7.2.39 of the BOINC client (which can be downloaded here), and you'll need the AMD APP (which can be downloaded here.)

2014-02-09: Deja Vu: World Record SR5 Discovery

On 6 February 2014, 16:02:23 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=22934 by finding the mega prime:

22934*5^1536762-1

The prime is 1,074,155 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 61st overall. This is the largest known base 5 mega prime. 86 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Keishi Toda (yuyusuke@jisaku) of Japan using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 14GB RAM running Microsoft Windows 7 Home Premium. This computer took about 9 hours and 2 minutes to complete the primality test using LLR. Keishi is a member of the Team 2ch team.

This is the second world record base 5 SR5 mega prime Keishi has discovered in approximately one week's time!

The prime was verified on 2 February 2014 0:15:42 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 21 hours and 34 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2014-02-02: Another Record SR5 Prime!

On 31 January 2014, 9:53:06 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=178658 by finding the mega prime:

178658*5^1525224-1

The prime is 1,066,092 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 61st overall. This is the largest known base 5 mega prime. 87 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Keishi Toda (yuyusuke@jisaku) of Japan using an Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz with 14GB RAM running Microsoft Windows 7 Home Premium. This computer took about 19 hours and 59 minutes to complete the primality test using LLR. Keishi is a member of the Team 2ch team.

The prime was verified on 2 February 2014 0:15:42 UTC, by smmistak of the United States using an Intel(R) Core(TM) i7-2700K CPU @ 3.50GHz with 16 GB RAM running Microsoft Windows 7 Ultimate. This computer took about 59 hours and 27 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-01-29: Tour de Primes 2014

Just like the past five years, PrimeGrid is offering a little side challenge in February: the Tour de Primes. You can run any subproject you like, be it via our BOINC server or our PRPNet servers. Unlike the regular challenges, this one will not give you challenge points for the challenge leader board but you can win a unique badge.

For more information, questions and general good fun please join us on our forums in this thread.

2014-01-24: World Record 321 Mega Prime Found!

On 14 January 2014, 15:26:41 UTC, PrimeGrid?s 321 Prime Search project found the mega prime:

3*2^10829346+1

The prime is 3,259,959 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 12th overall. This is the largest known 321 mega prime and the largest prime found to date at PrimeGrid!

The discovery was made by Sai Yik Tang (tomakey) of Malaysia using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 17 hours and 40 minutes to complete the primality test using LLR.

The prime was verified on 14 January 2014 20:23:24 UTC, by schnabelt of Germany using an Intel(R) Pentium(R) CPU G850 @ 2.90GHz with 4 GB RAM running Microsoft Windows 7 Enterprise. This computer took about 22 hours and 47 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2014-01-20: New SR5 Mega Prime Found!

On 17 January 2014, 6:53:10 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=59912 by finding the mega prime:

59912*5^1500861+1

The prime is 1,049,062 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 66th overall. This is the largest known base 5 mega prime. 40 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Raymond Ottusch (RaymondFO*) of the United States using an Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz with 24 GB RAM running Linux. This computer took about 3 hours and 41 minutes to complete the primality test using LLR. Raymond is a member of the Sicituradastra team.

The prime was verified on 17 January 2014 20:33:24 UTC, by Michael Wild (Tin Man) of the United Kingdom using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 4 GB RAM running Darwin. This computer took about 2 hours and 50 minute to complete the primality test using LLR. Michael is a member of the BOINC@AUSTRALIA team.

For more details, please see the official announcement.

2014-01-15: New SR5 Mega Prime Found!

On 29 December 2013, 18:56:35 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=37292 by finding the mega prime:

37292*5^1487989+1

The prime is 1,040,065 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 65th overall. This is the largest known base 5 mega prime. 41 k's now remain in the Sierpinski Base 5 Problem.

The discovery was made by Stephen R. Cilliers (SteveRC) of South Africa using an Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz with 8 GB RAM running Microsoft Windows 8.1. This computer took about 3 hours and 50 minutes to complete the primality test using LLR. Stephen is a member of the Clifford Welding Systems team.

The prime was verified on 30 December 2013 1:48:41 UTC, by [AF>France>Aquitaine>Cote-Adour-et-Gaves]Bernard 64250 of France using an Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz with 4 GB RAM running Microsoft Windows 7 Home Premium. This computer took about 5 hours and 1 minute to complete the primality test using LLR. [AF>France>Aquitaine>Cote-Adour-et-Gaves]Bernard 64250 is a member of the L'Alliance Francophone team.

For more details, please see the official announcement.

2014-01-15: New TRP Mega Prime Found!

On 25 December 2013, 11:53:21 UTC, PrimeGrid?s The Riesel Problem project eliminated k=40597 by finding the mega prime:

40597*2^6808509-1

The prime is 2,049,571 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 22nd overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 12th elimination. 52 k's now remain.

The discovery was made by Frank Meador (v149907) of the United States using an AuthenticAMD AMD Phenom(tm) 9500 Quad-Core Processor with 878 MB RAM running Linux. This computer took 29 hours 35 minutes to complete the primality test using LLR.

The prime was verified on 27 December 2013, 20:54:41 UTC, by Eliot Meadow of the United States using an Intel(R) Pentium(R) 4 CPU 2.80GHz with 2 GB RAM running Microsoft Windows XP Media Center. This computer took about 66 hours and 17 minutes to complete the primality test using LLR. Eliot is a member of the BOINCstats Team.


For more details, please see the official announcement.

2014-01-11: Fix for screen lag when running GPU

I'm putting this in the news/announcements because this may help people in many projects, not just PrimeGrid.

The downside to having an efficient GPU app is it's likely to produce a lot of screen lag. In some circumstances there's an easy fix that won't impact crunching speed.

If the lag is *only* happening in web browser windows, but not elsewhere, the problem is that the web browser is trying to use the GPU to speed up its screen rendering. That gets clobbered by the crunching happening on the GPU.

The browser should have a setting to enable or disable using the GPU, and it's enabled by default. Disabling GPU "acceleration" in the browser should completely eliminate the browser lag.

In Chrome, the setting is "Settings" -> "Show advanced settings" -> "Use hardware acceleration when available".

In Firefox, the setting is "Tools" -> "Options" -> "Advanced" -> "Use hardware acceleration when available".

It's likely a similar option exists in IE.

2014-01-08: Please update your Challenge selections!

We have had to modify the way you select CPU apps for the Year of the Horse -- Pony Express Challenge. The server was supposed to automatically choose the best (fasteft) of the three available CPU apps, but it wasn't.

You now must select the correct app manually. Please see this message for details.

I apologize for the inconvenience.

2013-12-30: Year of the Horse challenges start on January 3rd 2014, 18:00 UTC

With the start of the new year a new development in PrimeGrid challenges is about to take place. We will kick of of the 2014 challenge series with a dual challenge running on both the short (Pony Express edition) and the world record (Stallion Edition) Generalized Fermat Prime number search. Each will have their own scoreboard and you are free the participate in either or both of the challenges. Participants in the World Record category will however get 50% more challenge credit for the same position on the leaderboard.

The challenge will run for 15 days from January 3rd, 2014 18:00 UTC until January 18th, 2014, 18:00 UTC

For more information, assistance and cheery banter please do join us on the forums, either in the Stallion Edition thread or in the Pony Express Edition thread

2013-12-22: Get ready for the Year of the Horse DUAL Challenges!

It's not even Christmas yet, but it's time to start thinking about the simultaneous challenges we'll be running in early January.

Because of the very long run times of the tasks in these challenges, you might want to already be thinking about what you're running on your computers so they're available when the challenges start.

More information and discussion can be found here.

2013-12-18: First base 5 mega prime found!

On 4 December 2013, 20:53:51 UTC, PrimeGrid?s Sierpinski/Riesel Base 5 Problem project eliminated k=173198 by finding the mega prime:

173198*5^1457792-1

The prime is 1,018,959 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 67th overall. This is the first known base 5 mega prime. 88 k's now remain in the Riesel Base 5 Problem.

The discovery was made by Motohiro Ohno (syusui) of Japan using an Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz with 4GB RAM running Microsoft Windows 7 Home Premium. This computer took about 22 hours and 29 minutes to complete the primality test using LLR. Motohiro is a member of the Team 2ch team.

The prime was verified on 6 December 2013 5:27:38 UTC, by Scott Brown (Scott Brown) of the United States using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 8 GB RAM running Microsoft Windows 7 Home Premium. This computer took about 33 hours and 22 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

For more details, please see the official announcement.

2013-12-10: Winter solstice challenge starts Dec 18 17:11 UTC

Dear all,

The end of the year is drawing closer and this is traditionally marked with the winter solstice challenge here at PrimeGrid. As in previous years we would like to invite everyone to join us in this celebration of tidings of comfort and joy by sieving away for the Proth Prime Search. The challenge will start on Dec 18 17:11 UTC and last for 72 hours.

For more information, cheery banter and general merrymaking please join us on the discussion board.

We hope to see you there and please do spread the word :)

2013-11-04: Upgrading to OS X 10.9 (Mavericks) NOT recommended due to broken CUDA support

If you are currently running any BOINC CUDA projects (not just PrimeGrid) on an Nvidia GPU we recommend that you do NOT UPGRADE to OS X 10.9 (Mavericks) at this time.

According to the BOINC Wiki, the Nvidia CUDA driver is broken. After ugrading to OS X 10.9, you will likely be unable to run any BOINC CUDA tasks until Nvidia fixes the driver.

There's an ongoing discussion located here.

2013-11-01: Leonids Challenge starts November 14th, 18:00 UTC

November traditionally sees the skies lit up with falling stars a couple of nights during the Leonids meteor shower. Similarly on here on PrimeGrid November is the time for a challenge on our 321 LLR sub-project. This year the challenge will take place between November 14th 18:00 UTC and November 19th 18:00 UTC.

We hope that many of you will join us in this challenge and as always you can visit our forum for more useful information, cheery banter and some free roaming cows, rats, dogs, pigs and just regular users.

Please do spread the word and invite anyone to join us.

2013-10-17: Factorial Prime Found!

On 30 August 2013, PrimeGrid?s PRPNet found the 2nd largest known Factorial prime:

147855!-1

The prime is 700,177 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Factorial primes and 191st overall.

The discovery was made by Pietari Snow (Lumiukko) of Finland using an Intel(R) Core(TM) i7 CPU 940 @ 2.93GHz with 6 GB RAM running Linux. This computer took just a little over 69 hours and 37 minutes to complete the primality test using pfgw. Pietari is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2013-10-15: Another Record TRP Prime!

On 10 October 2013, 22:01:17 UTC, PrimeGrid?s The Riesel Problem project eliminated k=304207 by finding the mega prime:

304207*2^6643565-1

The prime is 1,999,918 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 11th elimination. 53 k's now remain.

The discovery was made by Randy Ready (cncr04s) of the United States using an Intel(R) Xeon(R) CPU X5570 @ 2.93GHz with 24 GB RAM running Windows Server 2003. This computer took 37 hours 36 minutes to complete the primality test using LLR. Randy is a member of the Aggie the Pew team.

For more details, please see the official announcement.

2013-10-10: New TRP Sieve File: Action required if you use app_info.

With the discovery of a new TRP prime, we've released an updated TRP Sieve file. No action is necessary on your part UNLESS you use app_info.xml.

If you use app_info.xml, please read this thread for more information about the MANDATORY update.

Update: One day later and there's another world record TRP prime, and another new sieve file. If you're running app_info, you need to grab the latest sieve file once again. See the thread above for details.

2013-10-10: World Record TRP Prime!

On 5 October 2013, 19:06:07 UTC, PrimeGrid?s The Riesel Problem project eliminated k=398023 by finding the mega prime:

398023*2^6418059-1

The prime is 1,932,034 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 10th elimination. 54 k's now remain.

The discovery was made by Vladimir Volynsky (Grey) of Russia using an Intel(R) Core(TM) i7- 3820 CPU @ 3.60GHz with 16 GB RAM running Windows 7 x64. This computer took 12 hours 43 minutes to complete the primality test using LLR. Vladimir is a member of the Russia team.

The prime was verified on 8 October 2013, 00:48:18 UTC, by Wolfgang Schwieger (DeleteNull) of Germany using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 16 GB RAM running Linux. This computer took 10 hours 4 minutes to complete the primality test using LLR. Wolfgang is a member of the Nemesis Germany team.

For more details, please see the official announcement.

2013-09-21: World Animal Day Challenge starts October 4th, 18:00 UTC

People have always had an interesting relationship with animals. We hunt them for food, we keep livestock for food too but we also use them for labor and keep them as pets and love them like family. In honor of this relationship there is a special day, World Animal Day. To mark this day, PrimeGrid invites every one to participate in the challenge starting at 1800 utc on October 4th, 2013 it will run for five days until October 9th, 2013, 18:00 UTC

For questions, banter, information you can go to this thread in our forums.

Please do spread the word and join the fun!

2013-09-13: GFN APPapalooza!

We have a veritable smorgasbord of GFN apps available now:

CPU:

There are three CPU versions of Genefer available for the short GFN tasks. The SSE2 version is the slowest and is sent to 64 bit hosts that don't support SSE3. (Only very early Athlon-64s don't support SSE3).

The new SSE3 version of Genefer is about 20% faster and is automatically sent to CPUs that support SSE3 (that's most CPUs).

The AVX version of Genefer is about 50% faster than the SSE2 version and is automatically sent to Linux and Mac hosts with CPUs that support AVX, i.e., Sandy Bridge and later CPUs. The server can't detect whether a Windows host supports AVX, so to get the faster GeneferAVX app on Windows you must explicitly tell the server to send it by checking the "Force AVX" box on the PrimeGrid Prefences page.

The SSE3 discussion is here and AVX is here.

ATI/AMD GPUs:

At long last we have an operational OpenCL version of Genefer that run on ATI/AMD GPUs. Double precision floating point hardware is required on the GPU.

Discuss OpenCL here, and the discussion about compatible ATI/AMD GPUs is here.

Nvidia GPUs:

In addition to the CUDA app we've been using, the OpenCL app for ATI/AMD is also available for Nvidia. Use whichever one runs faster on your hardware. In general, it seems as if CUDA is faster on older, pre-Kepler GPUs (GTX 5xx and older), and OpenCL is faster on newer Kepler GPUs (GTX 6xx and newer.)

Discuss OpenCL here, and the discussion about compatible Nvidia GPUs is here.

2013-09-10: OpenCL Genefer app available for ATI GPUs!

At long last, you can now run GFN and GFN World Record tasks on your ATI GPUs!

Only GPUs supporting double precision floating point are compatible with GFN.

This new OpenCL app can also be run on Nvidia GPUs. Sometimes the OpenCL app is faster; sometimes the CUDA app is faster. You can select whichever one runs faster on your system.

Discussion of GeneferOCL can be found here.

2013-08-25: PrimeGrid is now on Rackspace!

We've just moved PrimeGrid to new servers provided by Rackspace. (Thank you, Rackspace!)

Discussion and details can be found in this thread.

2013-08-16: Testers Needed for ATI/AMD GFN GPU App

Thanks to Yves Gallot, we now have a working OpenCL version of Genefer that runs on ATI/AMD GPUs.

If you have an ATI or AMD GPU and wish to run GFN tasks, or just want to help test, you can download the GeneferOCL app here and discuss running the new app in this thread.

Currently you must use the anonymous platform "app_info.xml" mechanism to run GeneferOCL.

At the present time only a Windows build is available (runs on 32 or 64 bit Windows).

2013-08-11: Perseid Shower Challenge Starts Tomorrow!

At 18:00 UTC tomorrow (Monday) our Perseid Shower Challenge featuring the Riesel Problem Sieve begins.

Please keep in mind that these tasks include a large sieve file that must be downloaded before the first task can be run, so it's a good idea to run one prior to the start of the challenge. (The sieve file only needs to be downloaded once no matter how many tasks you run.) It may take a while to download the necessary files when the challenge begins because there will be many thousands of computers all trying to access the server at the same time. Downloading the file early will help prevent delays in starting at the beginning of the challenge.

Also, for the very first time, we're officially supporting Android devices on this challenge. Feel free to connect your Android phone or tablet to www.primegrid.com and help crunch. We've made the TRP Sieve tasks 80% shorter to make it easier to crunch on mobile devices. (PrimeGrid doesn't yet show up automatically on the Android BOINC client, so you have to type the URL in.)

Finally, let's not forget the Perseid Shower itself. Weather permitting, don't forget to get outside and watch the meteor shower!

For more information on the Perseid Challenge, please see this thread.

2013-08-11: Perseid Shower Challenge is Almost Over

In a few short hours, the Perseid Shower will be ending. Thank you all for the your fantastic support.

Unlike in the past, sieve challenges now require a "cleanup" phase, so the same "end of challenge plea" applies:

At the Conclusion of the Challenge
We would prefer users "moving on" to finish those tasks they have downloaded, if not then please ABORT the WU's instead of DETACHING, RESETTING, or PAUSING.

ABORTING WU's allows them to be recycled immediately; thus a much faster "clean up" to the end of a Challenge. DETACHING, RESETTING, and PAUSING WU's causes them to remain in limbo until they EXPIRE. Therefore, we must wait until WU's expire to send them out to be completed.

Please consider either COMPLETING what's in the queue or ABORTING them. Thank you. :)

For more information on the Perseid Challenge, please see this thread.

I hope you had better weather for viewing the Perseids than I did!

2013-08-01: PrimeGrid Database Crash

At around 1609 UTC on Thursday, August 1st, PrimeGrid suffered an unrecoverable database crash which corrupted the BOINC database. We were unable to repair the database, or salvage the data.

We had to restore the database from last night's backup. The BOINC server was brought back on line at approximately 2120 UTC, with everything after the backup (at 0800 UTC) essentially having been erased.

Please go to http://www.primegrid.com/forum_thread.php?id=5196 for more details and discussion.

2013-07-30: Perseid Shower Challenge starting on 12 Aug 2013 18:00 UTC

The night sky can offer some wonderful sights, like distant stars and planets, the milkyway but also meteor showers. The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. Just like the star dust falling from the sky creating a good show, we'll hopefully be seeing candidates falling in similar fashion during the Perseid Shower Challenge on the Riesel Problem Sieve subproject. If you want to participate, please join us between 12 Aug 2013 18:00 UTC and end 14 Aug 2013 18:00 UTC.

For questions, banter, information you can go to this thread in our forums.

Please do spread the word and join the fun!

2013-07-21: AVX version of Genefer

I have enabled the AVX version of Genefer for GFN-short tasks. If you're running short GFN tasks on your CPU, and your CPU is AVX-capable, you will now get the AVX version.

This can be discussed in this thread: http://www.primegrid.com/forum_thread.php?id=5179.

2013-07-01: Fermat Divisor!

On 10 March 2013 17:07:02 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor:

183*2^1747660+1 Divides F(1747656)

The prime is 526,101 digits long and entered Chris Caldwell's The Largest Known Primes Database ranked 6th for prime Fermat divisors and 263rd overall.

The discovery was made by Bart van Rooijen of the Netherlands using LLR to complete the primality test. Bart van Rooijen is a member of the Dutch Power Cows team.

The prime was verified on 10 March 2013 by Aaron Everett of the United States using LLR to complete the primality test. Aaron Everett is a member of the Team USA team.

Due to a reporting error, the announcement of this find was missed back in March.

For more details, please see the official announcement.

2013-07-01: Fermat Divisor!

On 18 June 2013 16:51:36 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor:

2145*2^1099064+1 Divides F(1099061)

The prime is 330,855 digits long and entered Chris Caldwell's The Largest Known Primes Database ranked 10th for prime Fermat divisors and 2629th overall.

The discovery was made by Sai Yik Tang (tomakey) of Malaysia using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 4GB RAM running Microsoft Windows 7 Enterprise. This computer took about 8 minutes to complete the primality test using LLR.

The prime was verified on 21 June 2013 1:43:48 UTC by Timothy Hitch (Tim) using an Intel(R) Core(TM)2 Duo CPU T8300 @ 2.40GHz with 4 GB RAM running Microsoft Windows 7 Ultimate. This computer took about 33 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2013-06-25: Bonus Credit for Select Sub-Projects

In order to encourage greater participation in certain, less popular, sub-projects, we're experimenting with granting a credit bonus to select sub-projects.

Please see Bonus Credit Experiment for details.

2013-06-18: Wall-Sun-Sun Running Again!

Wall-Sun-Sun has been turned back on.

Please see this thread for more information.

2013-06-16: Long Duration SR5 Tasks May Be Prime

... so don't abort them!

If you notice that one of your SR5 tasks is running a LOT longer than usual, or even that it went back to 0% after reaching 100% done, DO NOT ABORT IT. You may have found a prime!

The test for base 5 Riesel numbers (i.e., of the form k*5^n-1) need to perform a second test if the first test indicates that the number may be prime, and the second test takes three times as long as the first test.

SR5 primes can be discussed here.

2013-06-11: Wall-Sun-Sun Shut Down Temporarily

Due to a problem with the GPU version of wwww, the Wall-Sun-Sun PRPNet server has been shut down until the problem is corrected. We do not expect the outage to last more than a couple of days.

Please see this thread for more information.

2013-06-01: Father's Day Challenge and SR5 go-live

Soon the new SR5 subproject will go live on BOINC. Soon in this case means on June 14th, the next day we will welcome this new project in style the Father's Day challenge will be held on this project.

NOTE that the boinc challenge has been moved 24 hours, the Father's Day Challenge will now start on June 15th 2013, at 18:00 UTC and will end on June 18th 2013, 18:00 UTC

Please spread the word, come join to honor fathers around the world or simply to get your hands on the shiny new SR5 badge that will of course be available!

For more information on the challenge, please visit the thread on the forum and feel free to ask any and all questions there.

As SR5 will be moved from PRPNet to BOINC, a challenge is also offered on the PRPNet port . The challenge will run from from June 9th until June 14th, or untill the port is dry. Whichever comes first. Will we be able to empty the port before the BOINC challenge? For cheery banter, information and directions on how to participate you can look at this thread
This PRPNET is a separate challenge from the main BOINC challenges and thus no challenge credit will be awarded, participants in the Father's Day Challenge are eligible for challenge credit.

2013-05-30: Validator temporarily shut down

I've shut down the validator while we investigate some anomalies with the validation process.

It's conceivable this could take a day or two, but it probably will only be a few hours.

While the validator is disabled, the "Workunits waiting for validation" number will continue to climb, and completed tasks will remain in the "pending" state.

I apologize for any inconvenience this may cause.

You can talk about it here.

2013-05-30: PPSE Has Left the Building!

The PPS (LLR) project has been split in two, with PPS retaining the longer PPS tasks and the shorter PPSE tasks now having their own project. The two are independently selectable on the PrimeGrid preferences page.

Statistics and badges for both types of tasks remain combined, so there's just one PPS (LLR) badge for both PPS and PPSE tasks.

The discussion about the PPS/PPSE split can be found here.

2013-05-28: Connectivity Problems with PRPNet

I've been informed that there's a DDOS attack happening right now against another client in the same datacenter as where the PRPNet server is located. That's causing the connectivity problems with PRPNet.

UPDATE: I have temporarily set up forwarding from the BOINC server to the PRPNet Server. You can therefore access the PRPNet ports by changing the prpclient.ini entries from prpnet.primegrid.com (or prpnet.mine.nu) to www.primegrid.com. However, if you have work in progress, you must also edit any work_xx.save files and point them to www.primegrid.com before restarting the client.

This is a temporary solution, so if you make this change, you'll need to eventually change back to the regular address. The forwarding will be taken down once the DDoS attack is ended.

UPDATE 2: The DDoS attack seems to be over (for now), so you should change your configuration to point back to prpnet.primegrid.com. I'll leave the port forwarding in place for a while, just in case.

2013-05-28: Extra Credit: SR5 Sieving Reopened!

In the near future, we're moving the SR5 (LLR) project from PRPNet to BOINC, and we need to do more SR5 sieving. We have therefore re-opened SR5 Manual Sieving. Instructions can be found on the SR5 Sieve Reservations page.

This is a CPU-based sieve.

As usual, manual PSA credit is available for sieving, but there's a twist this time: to spice things up, for a limited time we're offering DOUBLE CREDIT for sieving until SR5 goes live on BOINC!

Questions or comments can be made in this thread.

2013-05-28: PPS-Sieve OpenCL App for Mac/ATI Now Available

A long time ago in a gal..., er, well, in this galaxy, we used to be able to run the PPS-Sieve application on both Nvidia and ATI GPUs on Windows, Linux, and Mac OS.

Somewhere along the line the ATI app on Mac got broken and hasn't worked for a long time.

The app is once again working, so feel free to run PPS-Sieve on your ATI equipped Macs.

(For those who are interested, apparently what happened is that something like a year ago, I think something in Mac OS or the ATI drivers changed such that the Mac BOINC client couldn't detect that the drivers were present on the computer. As a result, it was telling the BOINC server that there were no drivers present, and the server therefore refused to send ATI apps to the client. The Mac BOINC client still isn't detecting the drivers, but I've modified the server to skip that check when the host computer is a Mac.)

To discuss this announcement, please go to this thread.

2013-05-27: "3-second" bug fixed

A bug affecting multiple Windows users on all LLR projects has been fixed. The problem was causing jobs to "complete" and claim success after about 3 seconds.

The problem was corrected by increasing the amount of permitted memory for each workunit. It seems as if some computers were exceeding the old limit. I'm not certain why that limit was being exceeded since BOINC was claiming that about 7 MB was being used and the limit was over 10 times as high, but increasing the limit has fixed the problem.

For more information or to discuss the problem, please see this forum thread.

2013-05-25: World Record Fermat Divisor!

On 13 May 2013 12:41:57 UTC, PrimeGrid's Proth Prime Search project found a world record prime Fermat divisor:

57*2^2747499+1 Divides F(2747497)

The prime is 827,082 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 1st for prime Fermat divisors and 101st overall. Incidentally, it is also a new record for "weighted" prime Fermat divisors.

The discovery was made by Marshall Bishop (Wintermute) of the United States using an AMD Quad-Core AMD Opteron(tm) Processor 2374 HE with 32 GB RAM running Linux. This computer took about 2 hours 28 minutes to complete the primality test using LLR.

The prime was verified by [AF>Le_Pommier>MacGeneration.com] Sloughi of France using an Intel(R) Xeon(R) CPU E5645 @ 2.40GHz with 12 GB RAM running Mac OS X. This computer took about 4 hour and 46 minutes to complete the primality test using LLR. [AF>Le_Pommier>MacGeneration.com]Sloughi is a member of the L'Alliance Francophone team.

For more details, please see the official announcement.

2013-05-18: PRPNet Port Migration

UPDATE: The move is scheduled for today, Saturday May 25th, at 14:00 UTC

We will soon be migrating all PRPNet ports on prpnet.mine.nu over to the prpnet.primegrid.com server.

Please see this thread for more information or to discussion the migration.

2013-05-16: Scheduled downtime Thursday evening

There will be a short downtime this evening, Thursday May 16th, between approximately 22:30 and 23:30 UTC on both the www.primegrid.com and prpnet.primegrid.com servers. Downtime is expected to be approximately 5 or 10 minutes.

2013-05-14: (More) Network Maintenance tonight (14-May) from 23:00 to 00:00 UTC

Deja vue all over again!

There will be work on the datacenter's network tonight, May 14th, from approximately 23:00 UTC until 00:00 UTC. This will affect only www.primegrid.com; prpnet.primegrid.com is in a different datacenter and will not be affected.

Short-term packet loss and/or increased latency may occur during this time period.

We apologize for any inconvenience this may cause.

2013-05-13: Network Maintenance tonight (13-May) from 23:00 to 00:00 UTC

There will be work on the datacenter's network tonight, May 13th, from approximately 23:00 UTC until 00:00 UTC. This will affect only www.primegrid.com; prpnet.primegrid.com is in a different datacenter and will not be affected.

Short-term packet loss and/or increased latency may occur during this time period.

We apologize for any inconvenience this may cause.

2013-05-05: New Badges!

After much arm twisting, hair pulling, pixel-wrangling, and a lot of great discussion, PrimeGrid (with a LOT of help from many of our participants) has extended the range of badges that can be earned.

There's now 18 different badge levels for each project. Many people will see new badge colors and shapes. The old badges were easily exceeded; at least one person had in excess of 1000 times the credit needed for our highest badge. That's the case no longer; your mega-achievements will now be recognized!

The new badge levels can be seen here, and you can discuss the new badges here.

Happy crunching!

2013-04-29: Low Country Festivities Challenge starts tonight at 18:00 UTC

At the end of April and start of May many festivities take place in the Lowcountries. We would like to invite you to join us to celebrate this with an 8 day challenge on the Woodal LLR subproject. The challenge starts on April 29th, 18:00 UTC and will end on May 7th, 18:00 UTC.

For more information, see the relevant thread on our forums.

We hope to see you there tonight and please spread the word.

2013-04-20: Cheaters' credits rescinded

At the end of February, we discovered that a small group of people were cheating by faking results. Changes were immediately made to our validation software to prevent this from happening again.

We have rescinded all the credits from the users who were cheating. To be fair, we've also deducted those credits from the teams they were in. Of course, not everyone in their teams are cheaters, but fraudulently gained credits shouldn't count towards team scores. Some of the teams affected are amongst the oldest, largest teams here, and in some cases those teams have lost in excess of 1 billion credits.

The other team members, no doubt, knew nothing of the cheating, so no stigma should be attached to these teams, or their members. I'm listing the teams here only so that if you suddenly see your team's credits and/or rank have dropped, you'll know why.

The following teams (team ID: team name) have lost credits:

64: BOINC@Taiwan
1: BOINCstats
103: Dutch Power Cows
2887: TaiwanROC
852: SETI@Taiwan รฏยฟยฝxรฏยฟยฝWรฏยฟยฝฮถรฏยฟยฝ

2013-04-16: Low Country Festivities Challenge April 29 - May 7

At the end of April and start of May many festivities take place in the Lowcountries. We would like to invite you to join us to celebrate this with an 8 day challenge on the Woodal LLR subproject. The challenge starts on April 29th, 18:00 UTC and will end on May 7th, 18:00 UTC.

For more information, see the relevant thread on our forums.

We hope to see you there and please spread the word.

2013-04-16: Server Upgraded, GPU/CPU bug fixed

I just installed new BOINC server software. The primary feature of the new server is that this should permanently fix the problem of erroneously getting CPU apps when you request GPU apps.

New with this release of the the BOINC server: CPU/GPU bug fixed. New PPS-Sieve, GFN (short), and GFN (WR) plan-classes. As a result of the new plan-classes, all host computers running these projects will need to download these applications again. In most cases, it's the exact same software as before, only with different names. Improved project selection: You now select GFN and GFN-WR independently. This allows you to use different shift override values for long and short tasks, and lets you choose CPU and GPU independently. If you select CPU tasks but have the "Use CPU" box unchecked, you get a warning that the tasks are disabled. The same applies to CUDA and ATI apps. If you turn on "Use CPUs" but don't select any tasks, PPS-LLR is automatically selected for you. Likewise, if you select "Use CUDA" or "Use ATI" and don't select any CUDA or ATI apps (respectively), PPS-Sieve (CUDA or ATI) will be selected for you. This prevents a situation where you host would continuously try to get work without the server being able to deliver any work because nothing is selected. New CUDA versions of GeneferCUDA have been installed for Windows and Linux. This is version 3.1.2-1 (2.05 in the BOINC numbering scheme), and improves CUDA error handling. The Mac version will be installed later when it becomes available.

2013-03-16: Equinox challenge starts in 26 hours

In 26 hours, at 11:02 AM UTC, March 17th the Equinox Challenge will start. This challenge will last for 5 days and takes place on the Proth Prime Search subproject. For more information, discussion and friendly banter please see the thread in our forums

Please do join and spread the word.

2013-03-12: Planned downtime tonight

There will be a short outage tonight as the servers are rebooted to make upgrades. This should happen sometime around 22:00 UTC tonight (March 12th). I expect this to take no more than 10 minutes, and the servers should come back up automatically.

Time zones being what they are, that's only about an hour from now.

2013-03-08: Equinox challenge 17 March - 22 March 18:00 UTC

People spending a lot of time on the internet will recognize the meme "Brace yourself, winter is coming!", as will readers and watchers of the Game of Thrones books and tv series. For those on the southern hemisphere that's what this Equinox challenge is all about. First the fall, then winter. For us on the Northern hemisphere though it's all about leaving winter behind us, nature starting to grow and showing us all its springtime beauty once again. Following that, we are very much looking forward to finding many new primes during this Equinox Challenge which is being offered on the Proth Prime Search subproject, from 17 March 18:00 till 22 March 18:00.

Please do join and spread the word.

For more information you can visit the thread on our forums.

2013-03-08: Equinox challenge 17 March - 22 March 11:02 UTC

People spending a lot of time on the internet will recognize the meme "Brace yourself, winter is coming!", as will readers and watchers of the Game of Thrones books and tv series. For those on the southern hemisphere that's what this Equinox challenge is all about. First the fall, then winter. For us on the Northern hemisphere though it's all about leaving winter behind us, nature starting to grow and showing us all its springtime beauty once again. Following that, we are very much looking forward to finding many new primes during this Equinox Challenge which is being offered on the Proth Prime Search subproject, from 17 March 11:02 till 22 March 11:02.

Please do join and spread the word.

For more information you can visit the thread on our forums.

2013-03-01: Serious CPU based PPS-Sieve Windows 32-bit problem

We've recently discovered a serious problem affecting some PPS Sieve tasks. The problem appears to be limited to 32 bit Windows systems running the sieve on the CPU.

Please see this post for more information or to leave a comment.

2013-02-27: Maintenance scheduled for Wednesday Feb 27th

On Wednesday February 27th, PrimeGrid's BOINC server will be taken down for performance upgrades, We estimate that this will take no more than approximately 2 hours.

The normally scheduled database backup that occurs at 0800 UTC will NOT be done, so the system won't be going down at 08:00.

I can't give you an exact start time, but we're planning on this starting around 12:00 UTC. The actual start time may be somewhat earlier or later.

I expect the forums to stay up during this process, and PRPNet will definitely stay up.

Thank you for your understanding.

2013-02-21: AVX enabled LLR apps now available on all 64 bit platforms

We just released the latest LLR 3.8.9 for all platforms. If you've been using app_info to enable use of AVX, you may not need to do so anymore.

Please see this post for more information.

Note: AVX support is not available for AMD Bulldozer CPUs.

2013-02-20: Server moves complete!

Both the PRPNet server and the BOINC server are now in their new locations, and no more extended outages are planned. Thanks you all for your patience during this move.

Special thanks go to Rytis and Lennart and especially Jim for all the work done during this sometimes hectic transition.

And thanks to everyone for your continued financial support, without which none of this would be possible!

2013-02-19: Scheduled PrimeGrid downtime 2013-02-20 00:00

There will be a short downtime at approximately 00:00 UTC tonight (about 3 hours from now) as some preventive maintenance is performed in the datacenter. The exact time of the outage may vary by as much as an hour.

Downtime is expected to be about 5 to 10 minutes.

2013-02-17: New LLR credit function

Your voices have been heard!

Well, we always heard you, but this wasn't the easiest thing to fix.

Anybody who has ever run any LLR project here probably noticed how seemingly random the credit was. Without going into detail, the variation was due to using the BOINC benchmark * CPU time method for calculating credit, which has lots of problems.

I've written a new credit function that is based soley on the complexity of the problem, so credit will be a lot more consistent than before.

We'll be turning the new credit system on one project at a time. You may notice that some projects will get more credit than before, and some may get less. The adjustment is to make it so that you get the same credit/hour regardless of which project you're crunching.

Currently, the new system is being used only for SGS. If nothing really bad happens, we'll start turning it on for the other projects. SGS used to have a fixed credit. It now varies slightly according to the size of the number. VERY slightly -- the difference is about 8 places past the decimal point, so you won't notice the difference, but it's there.

This should correct the following inequities with the old credit function: Identical Windows and Linux boxes scored differently on the BOINC benchmarks, and therefore got different credit for the same amount of work. Sandy and Ivy Bridge CPUs got LESS credit for being faster. Your wingmen would affect your credit, so if THEY have a Sandy Bridge CPU, you get penalized because their computer is fast. Hyperthreading and the effects of too-small CPU cache can cause crunching to slow down when all cores are in use, causing credit to go up because your computer is slower.
I'll keep you informed as the other projects are moved to the new system.

UPDATE: All LLR projects now use the new credit system.

EDIT: Added fourth bullet point about HT & cache misses causing higher credit as your computer slows down.

2013-02-13: PRPNet Server being moved -- TODAY!

All PRPNet ports on prpnet.primegrid.com have been brought down and are being moved to a new server.

Affected ports are GCW, Primorial, Factorial, GFN32768, GFN65536, 27, and 121.

All PRPNet ports running on prpnet.mine.nu are unaffected and are up.

At this time there's no ETA on restoration of the prpnet.primegrid.com ports.

We apologize for the short notice and the inconvenience. The timing of this was a surprise to us as well.

2013-02-07: Valentine's Day Challenge

February 14th is Saint Valentine's Day, a day generally used to express ones affection for someone special and we as prime hunters of course love Marie-Sophie Germain. She was born on April 1, 1776, in Paris, France. She was an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki)

PrimeGrid is offering a 24 hour challenge on Sophie-Germain Prime Search subproject, from February 14th, 18:00 UTC till February 15th, 18:00 UTC.

For more information, see this thread

2013-02-05: Donation drive for the server move

As you all may know, our datacenter is closing down and we are moving the servers of PrimeGrid soon. We are taking the opportunity to move to the cloud, which will reduce our costs and will allow to purchase additional resources when needed (for example, during the challenges).

However, PrimeGrid does not have any financial backing from universities or organizations. For the last year we have not been receiving enough money from donations and Google ads. Therefore, we have over 800? debt for the last year for collocation of the servers, and this year we have already added close to 300?. We also need the money for the purchase of new cloud services.

Because of this, we have to ask for your help. If you can help, please head to the donations page and make a contribution.

Each contribution, no matter how big or small, will earn you a donor's crown. However, we kindly ask you to keep the donation above 2? because of transaction fees.

We have also added a direct transfer in the following countries: Austria, Belgium, Czech Republic, Estonia, Germany, Lithuania, Latvia, The Netherlands, Poland, Slovakia, United Kingdom. We now also accept WebMoney. These donation types will be handled by our new payment processor, mokejimai.lt.

One tiny note: because of the server move, all donations will be handled and entered into the database manually, therefore it may take some time until your donation is processed and appears in the donation page.

So, once again, if you can - please head to the donation page and make a contribution. It is you who helps keep PrimeGrid running! Thank you for your support in advance. And if you have any questions, do not hesitate to contact any of the staff.

2013-01-25: Upcoming PrimeGrid Down Time

The BOINC server move is TENTATIVELY scheduled for Saturday, February 9th.

We are planning on moving PrimeGrid's BOINC system (www.primegrid.com) to a new server this coming Saturday, February 9th. The exact time of the move has not yet been determined. PrimeGrid's web server, forums, and BOINC will be down for as much as 24 hours while the transition is occurring.

The PRPNet server (prpnet.primegrid.com) will NOT be moving on Saturday, so the PRPNet ports and web pages should not be affected. PRPNet will move at a later, as yet undetermined date. PRPNet ports that will be eventually be affected when the PRPNet server is moved are: GCW, Primorial, Factorial, GFN32768, GFN65536, 27, and 121.

The PrimeSearchTeam forums, used for manual sieving, will not be affected and should remain up during the outage, as will the upload and download servers for manual sieving.

What should you do?

That depends on how much of a cache of work units you normally keep on your computer. If you're like me and keep either a very small cache, or no cache at all, you may want to increase the cache size in order to keep your computers busy during the outage.

Since the forums will be down along with the rest of the site, you can use our chatroom at http://www.chatzy.com/46334617429062 to get updates or to communicate with us. The chatroom is an external site and won't be affected by the outage. You may wish to save or bookmark that URL.

When will this happen?

The web server, forums, and BOINC server are scheduled to move on Saturday, February 9th. The exact time of day hasn't been decided yet.

The PRPNet server will be moving at a later date sometime in February.

Does this affect the upcoming challenges?

The server will be down for up to a day during the Tour de Primes, so make sure you have enough work on your computer to span the outage.

We've tried to schedule the move far enough ahead of the 14th so that the Valentine's Day challenge will not be affected. We're hoping the new server will be more powerful than the old server, so this may help with the challenge.

The effect on the ongoing cleanup phase for the Year of the Snake challenge should be negligible.

Will PrimeGrid's URL or IP address change?

The URL will not changing. The IP addresses WILL be changing. The process of converting to the new IP will be handled automatically by the DNS system and requires no action on your part, although it may take up to 24 hours for the mapping to propagate through the DNS servers. However, if for some reason you are using hard-coded IP address for PrimeGrid, you'll need to change them.

2012-12-29: Year of the Snake Challenge Annoucement

With the recent change to a larger short range for GFN and also the change of the year to the year of the Snake, PrimeGrid would like to invite everyone to participate in the first challenge of 2013!

A 13 day challenge is being offered on the Generalized Fermat project with short work units. This is only the second challenge of its kind we're offering, and because the work units will grow too big for a challenge after this it's mighty likely there won't be another one. So have you always dreamed of finding a gigantic prime (top 15 for sure, maybe even top 10!), then this is your chance! Join us from January 4 2013, 18:00 UTC till January 17 2013, 18:00 UTC and see what's going on.

For more information on this challenge, please read this thread on our forums and feel free to leave a comment or ask any questions you might have.

2012-12-15: Winter Solstice Challenge Reminder

In just over two days the Winter Solstice Challenge will start.

For those of us in the Northern Hemisphere, the full force of Winter is soon here. Please come join us in observing one of Nature's way-points...the Winter Solstice.
A 3 day (18-21 Dec) Winter Solstice Challenge is being offered on the Proth Prime Search (Sieve) application. 32 & 64 bit builds are available for Mac, Linux, and Windows as well as CUDA/ATI (OpenCL) for the GPU.

This will conclude PrimeGrid's 2012 Challenge series. For more information and banter, please see this forum thread.

2012-12-02: Winter Solstice Challenge

For those of us in the Northern Hemisphere, the full force of Winter is soon here. Please come join us in observing one of Nature's way-points...the Winter Solstice.
A 3 day (18-21 Dec) Winter Solstice Challenge is being offered on the PPS (Sieve) application. 32 & 64 bit builds are available for Mac, Linux, and Windows as well as CUDA/ATI (OpenCL) for the GPU.

This will conclude PrimeGrid's 2012 Challenge series. For more information, please see this forum thread.

2012-11-12: PPS Mega Prime!

On 2 November 2012, 3:47:30 UTC, PrimeGrid?s Proth Prime Search project found the Mega Prime:

7*2^5775996+1

The prime is 1,738,749 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 24th overall.

The discovery was made by Martyn Elvy (Martyn Elvy) of New Zealand using an Intel(R) Xeon(R) CPU E5345 @ 2.33GHz with 3GB RAM, running Windows Server 2003. This computer took just over 11 hours 16 minutes to complete the primality test using LLR. Martyn is a member of the NZ.BOINC team.

The prime was verified by Robert Ruge (robert) of Australia using an Intel(R) Xeon(R) CPU X5650 @ 2.67GHz with 10 GB RAM, running Linux. This computer took just under 6 hours 24 minutes to complete the primality test using LLR.

For more details, please see the official announcement.

2012-11-06: PPS Mega Prime!

On 23 October 2012, PrimeGrid?s Proth Prime Search project found the Mega Prime:

9*2^3497442 +1

The prime is 1,052,836 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 51st overall. This prime is also a Generalized Fermat prime and ranks as the 12th largest found.

The discovery was made by Heinz Ming (parabol) of Switzerland using an Intel Core(TM) i7 CPU 860 @ 2.80GHz with 8GB RAM, running Windows 7 Professional. This computer took just over 5 hours 59 minutes to complete the primality test using LLR. Heinz Ming is a member of the Aggie The Pew team.

The prime was verified by Tim McArdle (Bauerwulf) of the United States using an AMD Athlon(tm) II P340 Dual-Core Processor with 6 GB RAM, running Windows 7 Professional. Jason is a member of the Don't Panic Labs team.

For more details, please see the official announcement.

2012-10-30: 321 Blast Off Challenge! Reminder !!

Calling all crunchers! November 1st is drawing close, and on that day at 18:00 UTC PrimeGrid will launch into the 321 Blast Off Challenge on the 321 LLR subproject. We will be flying at top speed untill November 9th, 18:00 UTC by which time we hope to return safely to the ground with some magnificent results. Please feel free to join us by selecting the 321 LLR subproject on your accounts preference page. For more information and banter, join us on the forum!

And as always, please spread the word.

2012-10-22: 321 Blast Off Challenge! on PrimeGrid

321 Blast Off Challenge!

Calling all crunchers! November 1st is drawing close, and on that day at 18:00 UTC PrimeGrid will launch into the 321 Blast Off Challenge on the 321 LLR subproject. We will be flying at top speed untill November 9th, 18:00 UTC by which time we hope to return safely to the ground with some magnificent results. Please feel free to join us by selecting the 321 LLR subproject on your accounts preference page. For more information and banter, join us on the forum!

And as always, please spread the word.

2012-10-03: An Apple a Day Challenge (Reminder)

Two days left to start !!

On October 5th at 18:00 UTC PrimeGrid's 2012 Challenge Series will see its next episode. The 'An Apple a Day' challenge is held on the Proth Prime Search (LLR) subproject and will last 24 hours. Work units will be very short, so every minute will count!

For more information please visit this topic on the forums.

Please spread the word on the challenge and hope to see you all on October 5th.

2012-09-11: An Apple a Day Challenge

On October 5th at 18:00 UTC PrimeGrid's 2012 Challenge Series will see its next episode. The 'An Apple a Day' challenge is held on the Proth Prime Search (LLR) subproject and will last 24 hours. Work units will be very short, so every minute will count!

For more information please visit this topic on the forums.

Please spread the word on the challenge and hope to see you all on October 5th.

2012-08-21: World Record GFN Prime!

On 8 Aug 2012, 8:58:58 UTC, PrimeGrid?s Generalized Fermat Prime Search found the largest known Generalized Fermat mega prime:
475856^524288+1

The prime is 2,976,633 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat primes and 11th overall.

The discovery was made by Masashi Kumagai (ragnarag) of Japan using an NVIDIA GeForce GTS 450 in an AMD FX(tm)-8150 CPU with 8GB RAM, running 64 bit Windows 7. This GPU took 7 hours 47 minutes to probable prime (PRP) test with GeneferCUDA. Masashi Kumagai is a member of the Team 2ch team.

The prime was verified by Jason Preszler (Jason Preszler) of the United States using an Intel Core i7-2600 CPU @ 3.40GHz with 12GB RAM, running 64 bit LINUX . This computer took 46 hours 55 minutes to probable prime (PRP) test with GenefX64. Jason is a member of the Turan@BOINC team.

For more details, please see the official announcement.

2012-07-31: An Apple a Day Challenge

PrimeGrid's 2012 Challenge Series continues with the "An Apple a Day Challenge".

PrimeGrid is offering 48 hr Challenge (3-5 Aug) on The Riesel Problem (Sieve) application. For more information, please see this forum post

p.s. Please spread the word about An Apple a Day Challenge.
____________

2012-07-31: An Apple a Day Challenge (Olympics)

PrimeGrid's 2012 Challenge Series continues with the "An Apple a Day Challenge".

PrimeGrid is offering 48 hr Challenge (3-5 Aug) on The Riesel Problem (Sieve) application. For more information, please see this forum post

p.s. Please spread the word about An Apple a Day Challenge.
____________

2012-07-31: The Olympics Challenge

PrimeGrid's 2012 Challenge Series continues with the "Olympics Challenge".

PrimeGrid is offering 48 hr Challenge (3-5 Aug) on The Riesel Problem (Sieve) application. For more information, please see this forum post

p.s. Please spread the word about the Olympics Challenge.

2012-07-25: World Record GFN Prime!

On 20 Jun 2012, 4:26:47 UTC, PrimeGrid?s Generalized Fermat Prime Search found the largest known Generalized Fermat mega prime: 356926^524288+1

The prime is 2,911,151 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat primes and 11th overall.

The discovery was made by (bherbihyewrbg) of Japan using an NVIDIA GeForce GT 640M in an Intel Core i7-3610QM CPU @ 2.30GHz with 8GB RAM, running 64 bit Windows 7 Professional. This GPU took 17 hours 49 minutes to probable prime (PRP) test with GeneferCUDA. (bherbihyewrbg) is a member of the Team 2ch team.

The prime was verified by Tim McArdle (Bauerwulf) of the United States using an Intel Core i7-2600 CPU @ 3.40GHz with 8GB RAM, running 64 bit Windows Server 2008 . This computer took 43 hours 46 minutes to probable prime (PRP) test with GenefX64. Tim is a member of the Don't Panic Labs team.

For more details, please see the official announcement.

2012-06-28: World Record GFN Prime!

On 15 Jun 2012, 9:27:36 UTC, PrimeGrid?s Generalized Fermat Prime Search found the largest known Generalized Fermat mega prime: 341112^524288+1

The prime is 2,900,832 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat primes and 11th overall.

The discovery was made by Peyton Hayslette (Peyton Hayslette) of the United States using an NVIDIA GeForce GTX 560 Ti in an Intel Core i5-2500K @ 3.30GHz system with 16GB RAM, running 64 bit Windows 7 Ultimate. This GPU took 3 hours 48 minutes to probable prime (PRP) test with GeneferCUDA. Peyton is a member of the North Carolina team.

The prime was verified by Rob Bosma (Cow_tipping) of the Netherlands using an NVIDIA GeForce GTX 580 in an Intel Core i7 920 @ 2.67GHz with 16GB RAM, running 64 bit Windows 7 Ultimate. This GPU took 2 hours 26 minutes to probable prime (PRP) test with GeneferCUDA. Rob is a member of the Dutch Power Cows team.

For more details, please see the official announcement.

2012-06-27: GFN Sieving

There's an ongoing effort to finish up the GFN sieves. If you have Windows and a CUDA capable card, please consider participating in this manual sieve effort. See GFN Prime Search (GPU Sieving) for instructions. It's another good way to earn your PSA badge.

Wellcome

PrimeGrid/Admins

2012-06-25: A Request for Assistance

We are attempting to reach a BOINC user who found one of the recent GFN mega primes?ranked 11th in the World! We are seeking help from the BOINC community in finding this individual. (bherbihyewrbg) of Japan and Team 2ch

If you have contact with this individual, please have them check their BOINC emails or private messages in PrimeGrid's forum. Several attempts have already been made through these channels. Additionally, if you have any information that might help us in contacting this individual, please contact us here: http://www.primegrid.com/contact.php

2012-06-25: World Record TRP Prime!

On 23 June 2012, 7:58:18 UTC, PrimeGrid?s The Riesel Problem project eliminated k=252191 by finding the mega prime: 252191*2^5497878-1

The prime is 1,655,032 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 21st overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 9th elimination. 55 k's now remain.

The discovery was made by Jan Haller (Janita) of Germany using an Intel Pentium Dual-Core E5400 @ 2.70GHz with 4 GB RAM running Windows 7. This computer took over 17 hours 30 minutes to complete the primality test using LLR.

The prime was verified on 23 June 2012, 15:35:21 UTC, by Tony Gott (bayanne) of the United Kingdom. Tony is a member of the Ars Technica team.

For more details, please see the official announcement.

2012-06-22: World Record GFN Prime Found...Twice!

Just prior to the start of the Alan Turing Year Challenge, not one, but two GFN mega primes were found! When all is finalized, these will be the 11th and 12th largest primes found to date and will be the two largest primes found by PrimeGrid. These are each incredible finds!

Internal verification of these primes is ongoing, and for primes of this size, will take a few days. Stay tuned for the official announcement.

There's still more than half of the challenge to go...Let's see if we can make it three (or more)! :)

2012-06-18: Prime Fermat Divisor Found

Congratulations to Robert Boniecki (Robert) of the United States, the discoverer of PrimeGrid's 12th Prime Fermat Divisor in the Proth Prime Search project: 1705*2^906110 + 1 Divides F(906108). This is the 298th known divisor and the 6th found in 2012 (4th by PrimeGrid). The prime is 272,770 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 9th for prime Fermat divisors and 2359th overall. Additionally, it ranks 1st in the Weighted Record Primes of this type at the Prime Pages.

For more details, please see the official announcement.

2012-06-17: Welcome to the Alan Turing Year Challenge

A 3 day Challenge is being offered on PrimeGrid's Generalized Fermat Number (GFN) application. Only SHORT Work Units may be used in this challenge. To participate in the Challenge, please select only the Generalized Fermat Prime Search project and also select Short tasks in your PrimeGrid preferences section. (The longer World Record GFN tasks can't be completed within the 3 day span of this challenge.) You may leave the Block Size setting at 0.

The challenge will begin 20 June 2012 23:09 UTC and end 23 June 2012 23:09 UTC.

IMPORTANT IMPORTANT !!

Read this post:http://www.primegrid.com/forum_thread.php?id=4411&nowrap=true#55369

Wellcome :)

2012-06-03: Prime Fermat Divisor Found

Congratulations to James Boerner (NullCoding*) of the United States, the discoverer of PrimeGrid's 11th Prime Fermat Divisor in the Proth Prime Search project: 7905*2^352281 +1 Divides F(352279). This is the 297th known divisor and the 5th found in 2012 (3rd by PrimeGrid). James is a member of the Sicituradastra. team.

For more details, please see the official announcement.

2012-05-02: The Cinco de Mayo Challenge. May 5 18:00 UTC

Come join us for the 5th day of the 5th month celebration. A 5 day Challenge is being offered on PrimeGrid's "The Riesel Problem" (LLR) applicationยฆends on the 10th. There remains 56 k's in The Riesel Problem for which no primes have been found.

For more information, please see this forum post.

2012-04-23: End-of-life for current iteration of Sophie Germain Prime Search

Because of the recent discovery and exhaustion of the search range, current iteration of Sophie Germain project is being finished. No new work will be inserted, and only some resends for unfinished work will be issued. There are plans to restart Sophie Germain search in the future: we are evaluating best approach to the problem at the moment.

If you have opted only into Sophie Germain project, we suggest revising your project preferences and selecting other projects so that you keep receiving work.

2012-04-23: Generalized Fermat Mega Prime

On 19 Apr 2012, 21:12:27 UTC, PrimeGrid?s Generalized Fermat Prime Search, through PRPNet, found the mega prime: 773620^262144+1

The prime is 1,543,643 digits long and enters Chris Caldwell's ?The Largest Known Primes Database? ranked 2nd for Generalized Fermat primes and 22nd overall.

The discovery was made by Senji Yamashita of Japan using an NVIDIA GeForce GTX 580 in an Intel Core i7-970 @ 3.20GHz system with 6GB RAM, running Windows 7 Professional x64. This GPU took about 47 minutes to probable prime (PRP) test with GenefCUDA. Senji is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2012-04-17: World Record Sophie Germain prime found!

On 9 April 2012 6:31:14 UTC, PrimeGrid?s Sophie Germain Prime Search found a World Record Sophie Germain prime: 18543637900515*2^666667-1 (2p+1: 18543637900515*2^666668-1)

The prime is 200,701 digits long, eclipsing the previous record of 79,911 digits. It enters Chris Caldwell's ?The Largest Known Primes Database? ranked 1st for Sophie Germain primes.

The discovery was made by Philipp Bliedung (pabliedung) of the United States using an Intel Core i7 950 @ 3.07GHz with 12 GB RAM running Linux. Philipp is a member of the USA team.

The prime was verified on 9 April 2012 9:36:15 UTC, by Lee Blyth (IshtarIS) of Australia using an Intel Core i7 2600k @ 3.40GHz with 8 GB RAM running Windows 7 Ultimate. Lee is a member of the Ishtar team.

For more details, please see the official announcement.

2012-04-11: March was a great month for the Extended Sierpinski Problem project

March was a special month for the Extended Sierpinski Problem (ESP) on PrimeGrid's PRPnet. After two years of crunching with no prime finds, two more k's were eliminated:

The first discovery was made by Timothy D. Winslow (Pooh Bear 27) of the United States on Wednesday 14th of March 2012. 123287*2^2538167+1 is prime and at 764070 digits entered Chris Caldwell's Top 5000 list as the 78th largest prime.

The second discovery was made by Rodger Ewing (Pilgrim) of the United States on Tuesday 27th of March 2012. 147559*2^2562218+1 is prime and at 771310 digits entered Chris Caldwell's Top 5000 list as the 77th largest prime.

15 k's now remain.

Congratulations to both Rodger and Tim! The next ESP find will very likely also be a Mega Prime!

For more information about the Extended Sierpinski Problem, see this forum post.

2012-04-01: The Marie Sophie Germain Challenge 2012 starts in 6 hr. :)

Marie-Sophie Germain was born on April 1, 1776, in Paris, France. She was an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki) Come join us as we pay tribute to her with a 2 day (1-3 April) Challenge on the Sophie Germain Prime Search project.

For more information, please see this forum post.

2012-03-29: The Marie Sophie Germain Challenge 2012 starts in 3 days

Marie-Sophie Germain was born on April 1, 1776, in Paris, France. She was an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki) Come join us as we pay tribute to her with a 2 day (1-3 April) Challenge on the Sophie Germain Prime Search project.

For more information, please see this forum post.

2012-03-02: World Record Primorial prime

On 28 Feb 2012, PrimeGrid?s Primorial Prime Search, through PRPNet, has found a world record primorial prime: 1098133#-1

The prime is 476,311 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Primorial primes and 253rd overall.

The discovery was made by James P. Burt (jpaul) of the Cayman Islands using an AMD Phenom 9750 Quad-Core @ 2.4GHz with 4 GB RAM running Windows 7 Professional x64. James is a member of the Aggie_The_Pew team.

This is only the 20th known p#-1 Primorial prime and the 2nd discovered in the last 20 years. For more details, please see the official announcement.

2012-02-28: 27 Mega Prime

On 28 Feb 2012, 15:51:22 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search (k=27 sister project), has found the mega prime: 27*2^3855094-1

The prime is 1,160,501 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 34th overall. This is PrimeGrid's 23rd mega prime.

The discovery was made by Pietari Snow (Lumiukko) of Finland using an Intel Intel Xeon E5410 @ 2.33GHz with 12GB RAM, running Microsoft Windows Server 2003 64 bit. This computer took just over 4 hours 13 minutes to complete the primality test using LLR. Pietari is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2012-02-28: The Leap Day Challenge - "Just for Fun"

Four significant issues over the last six days in the run-up to the Leap Day Challenge has created so much havoc that it is prudent the Challenge be "changed". There are simply too many obstacles to overcome in such a short time span. Additionally, it is unknown when Nvidia will resolve the sleep issues related to the 295.73 driver.

The Leap Day Challenge will still be offered, stats will be provided, but only on a "Just for Fun" basis. For more details about the issues and the effect this will have on the annual Challenge Series, please see this post.

2012-02-27: Nvidia driver 295.xx problems

We are seeing an elevated error rate from hosts using Nvidia drivers 295.xx.

If your monitor is put to sleep by the computer, the GPU is no longer available as a CUDA device. This will cause an immediate failure of any CUDA WUs. This includes GFN/Genefer, PPS Sieve, GCW Sieve, and llrCUDA.

In the mean time we can only suggest not to upgrade to this version (or downgrade if already installed), or disable power saving in the system.

We will update once we have more information.

2012-02-26: The Leap Day Challenge in 3 days

Leap Day 2012 is just 3 days away. While you are off enjoying your extra day, having a good time, your computer sits at home envious. Why not give it something fun to do as well? Come join the Leap Day Challenge, a 24 hour Challenge offered on PrimeGrid's Cullen/Woodall (Sieve) application.

For more information, please see this forum thread.

2012-02-26: 121 Mega Prime

k=121 has finally opened its vault. After 6 years of stubbornness, it relinquishes its strong hold on primes. On 25 Feb 2012, 06:34:08 UTC, PrimeGrid?s 27121 Prime Search, through PRPNet and in collaboration with the 12121 Search, has found the mega prime: 121*2^4553899-1

The prime is 1,370,863 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 28th overall. This is PrimeGrid's 22nd mega prime.

The discovery was made by Timothy D. Winslow (Pooh Bear 27) of the United States using an Intel Intel i7 930 @ 2.8GHz with 12GB RAM, running Microsoft Windows 7 Home Premium 64 bit. This computer took just over 5 hours 49 minutes to complete the primality test using LLR. Timothy is a member of the The Knights Who Say Ni! Team.

For more details, please see the official announcement.

2012-02-22: The Leap Day Challenge in 7 days

What to do with an EXTRA day in the year??? One could take a nap, read a book, go skiing/walking/hiking/swimming/etc, spend time with family, watch your favorite movie...and the list goes on and on. :) However, what your computer can do with an extra day is easy...come join the Leap Day Challenge, a 24 hour Challenge offered on PrimeGrid's Cullen/Woodall (Sieve) application.

For more information, please see this forum thread.

2012-02-18: Tour de Primes 2012 - Mountain Stage

The mountain stage is finally upon us. The coveted polka-doted jersey will go to the participant who finds the most primes between 19 Feb 2012 00:00 UTC and 20 Feb 2012 00:00 UTC. In case of a tie, the combined prime score will determine the winner. For more information about the tour, please see Tour de Primes 2012

UPDATE: Mountain stage extended to 48 hours to accommodate a policy update. Runs between 19 Feb 2012 00:00 UTC and 21 Feb 2012 00:00 UTC.

Best of Luck to everyone!

2012-02-14: February's PRPNet Challenge Project

The Wieferich Prime Search is PrimeGrid's PRPNet Challenge project for February...dubbed the "Wild Whacky Whimsical Wednesday" (WWWW) Challenge. This is the 2nd Challenge in the 2012 PRPNet Challenge Series.

The 24 hour Challenge will run from 15 February 2012 00:00 UTC to 16 February 2012 00:00 UTC. This is for those users who wish for a bit more variety in their prime search endeavors and don't mind venturing outside of BOINC to PRPNet. :) It's a relaxed and informal environment so stop by and see what you think.

For more information, please see this thread.

2012-02-13: Generalized Fermat Mega Prime

On 12 Feb 2012, 3:48:23 UTC, PrimeGrid?s Generalized Fermat Prime Search found the mega prime: 676754^262144+1

The prime is 1,528,413 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat Primes and 23rd overall. This is the 2nd Top 25 prime in 3 weeks. A nice beginning for the new Generalized Fermat Prime Search. The primes are only going to get bigger. :)

The discovery was made by Carlos Loureiro of Portugal using an NVIDIA GeForce GTX 550 Ti in an Intel Core i5-2500K @ 3.30GHz system with 4GB RAM, running Windows 7 Ultimate x64. This GPU took about 1 hour 30 minutes to probable prime (PRP) test with GenefCUDA. Carlos is a member of the Blasfemias team.

The PRP was verified on 12 Feb 2012, 8:33:09 UTC, by Peter Verstappen of Australia. For more details, please see the official announcement.

2012-02-07: Prime Fermat Divisor Found

Congratulations to Rob Derrera (TEAM BIGDOG) of the United States, the discoverer of PrimeGrid's 10th Prime Fermat Divisor in the Proth Prime Search project: 131*2^1494099+1 Divides F(1494096). This is the 294th known divisor and the 2nd found in 2012. Rob is a member of the US Navy team.

For more details, please see the official announcement.

2012-02-04: Generalized Fermat Prime Search

The Generalized Fermat Prime Search is now out of beta and open to all users. An Nvidia GPU with double precision floating point hardware is required for this project. Also, MacIntel CPU's are supported at the current N=262144 (b^2^18).

A wealth of discussion has been gathered during the beta phase. For any issues or questions, please see the Generalized Fermat Prime Search forum.

This search will eventually reach N=4194304 (b^2^22) which, if successful, has the potential of discovering the world's largest known prime number. Current testing times at N=262144 are ~1 hr for fast GPU's and ~7 hrs for fast MacIntel CPU's.

Best of Luck to everyone!

2012-02-03: Call for arms: full doublecheck of TRP

We have recently started a limited doublecheck effort for The Riesel Problem and this has very quickly yielded a prime, which means that the results that we obtained from Riesel Sieve project cannot be trusted 100%. Therefore we have decided to run a full doublecheck effort.

We would like to quickly go through the doublecheck ranges and resume our original search, so we would like to ask you to consider redirecting any resources you may have available to The Riesel Problem (TRP) subproject. You can do that by visiting project preferences page.

Applications are available for Windows, Linux and Mac. 32bit applications will be sent to 64bit hosts.

2012-02-03: Prime found for the Riesel Problem

On 2 Feb 2012, 21:30:55 UTC, PrimeGrid?s The Riesel Problem project eliminated k=162941 by finding the prime: 162941*2^993718-1

The prime is 299,145 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 1536th overall. This prime was found while exploring a suspected gap in a previously searched range. This is PrimeGrid's 8th elimination. 56 k's now remain.

The discovery was made by Dmitry Domanov (unconnected) of Russia using an Intel Xeon @ 3.60GHz with 2 GB RAM running Windows Server 2003 Enterprise x86. This computer took just over 1 hour 5 minutes to complete the primality test using LLR. Dmitry is a member of Team Russia.

For more details, please see the official announcement.

2012-02-01: The Tour de Primes Begins!

Come join us in laid-back competition in tribute to the number 2...the first prime and the only even prime. The prizes are simple colored jerseys . Yellow for the most primes, Green for the highest prime score, and Polk-a-dot for the most primes on 19 Feb. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2012.

2012-01-30: World Record Generalized Cullen Prime

On 29 Jan 2012, 08:10:03 UTC, PrimeGrid?s PRPNet found the largest known generalized Cullen prime: 427194*113^427194+1

The prime is 877,069 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for generalized Cullen primes and 57th overall.

The discovery was made by Ricky L. Hubbard of the United States using an AMD Phenom II X6 1090t @ 3.2GHz with 8GB RAM, running Windows 7. This computer took 7 hours and 15 minutes to complete the probable prime test using pfgw64 and 7 hours 20 minutes to complete the primality test again using pfgw64. Ricky is a member of the AMD Users Team.

For more details, please see the official announcement.

2012-01-24: Tour de Primes 2012

February is just a week away which means it is time for the 4th annual Tour de Primes. 2 is the first prime number...and the only even one. Therefore, we have declared February, the 2nd month, as prime month.

We're offering a small informal competition in tribute to this unique prime number. There are no points to be gained or awards to be won...just a simple rare jersey (Yellow, Green, and Polk-a-dot) at the end of the month to add to your badge collection. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2012.

2012-01-22: The Year of the Dragon in 24 hours

The Dragon, the mightiest of all the signs, is a creature of myth and legend. In Asia, the Dragon is an auspicious creature, a symbol of benevolent power, strength and good luck and capable of great good. 23 January 2012 marks the start of the Year of the Dragon. Let's see if we can channel that Dragon energy to find some primes for the start of PrimeGrid's 2012 Challenge Series.

A 5 day Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. For more information, please see this forum thread.

2012-01-22: Generalized Fermat Mega Prime

On 18 Jan 2012 21:13:24 UTC, PrimeGrid?s Generalized Fermat Prime Search found the mega prime: 525094^262144+1

The prime is 1,499,526 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat Primes and 24th overall.

The discovery was made by David Tomecko of the United States using an NVIDIA GeForce GTX 570 in an Intel Core i7 980 @ 3.33GHz system with 24GB RAM, running Windows 7 Ultimate. This GPU took about 55 minutes 24 seconds to probable prime (PRP) test with GenefCUDA. David is a member of the The Knights Who Say Ni! team.

The PRP was verified on 19 Jan 2012 7:37:53 UTC, by Rick Reynolds of the United States. For more details, please see the official announcement.

2012-01-18: Mega Prime Found

On 17 Jan 2012 20:24:07 UTC, PrimeGrid?s Mega Prime Search, through PRPNet, found the Mega Prime: 81*2^3352924+1

The prime is 1,009,333 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 42nd overall. This prime is also a Generalized Fermat prime and ranks as the 6th largest found.

The discovery was made by Micha? Gasewicz of Poland using an Intel dual Xeon E5520 @ 2.27GHz with 12GB RAM, running 64 bit Linux. This computer took just over 4 hours 28 minutes to complete the primality test using LLR. Micha? is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2012-01-09: AVX build of llr

Gary Craig, a member of Aggie The Pew, was successful in compiling an AVX version of LLR using gwnum v27.2 and LLR v3.8.6dev. We've been testing it for the past week with success. Depending on the LLR project, speed improvements range from 20% to 50%.

For more details, please see this post

2012-01-06: Prime Fermat Divisor Found

Congratulations to Bruce Dodson (bdodson*) of the United States, the discoverer of PrimeGrid's 9th Prime Fermat Divisor in the Proth Prime Search project: 329*2^1246017+1 Divides F(1246013). This is the 293rd known divisor and the 1st found in 2012. Bruce is a member of the Sicituradastra. team.

For more details, please see the official announcement.

2012-01-01: Welcome to 2012

The New Year is here and so to are a couple of new projects at PrimeGrid. The Wieferich and Wall-Sun-Sun prime searches are now available through PrimeGrid's PSA PRPNet. Already in beta testing, a new "near" Wieferich prime (|A|
This first week of 2012 is planned as a home warming party. Please stop by, crunch a few WU's and read up more about these extremely rare and unique primes. For more information, please see A week of Wieferich and Wall-Sun-Sun.

2011-12-31: 2011 Challenge Series Final Rankings

PrimeGrid's 2011 Challenge Series is final. Another incredible year of growth and competition...so much so that the servers were stressed again on a few Challenges. A tremendous about of work was accomplished leading to some pretty special primes found this year.

Congratulations to Sicituradastra. as the top team and Snf* as the top individual. They are the winners of PrimeGrid's 2011 Challenge Series. For complete, extended rankings please see: Individuals | Teams

As always, thank you for your help and support. We continue to be humbled by your participation. None of this is possible without YOU! :) Have a safe and happy Holiday season. See you next year for PrimeGrid's 2012 Challenge Series!

2011-12-26: World Record Twin Primes

On 25 Dec 2011 13:31:28 UTC, PrimeGrid's Sophie Germain Prime Search found World Record Twin Primes: 3756801695685*2^666669ยฑ1

The twin primes are 200,700 digits long, eclipsing the previous record of 100,355 digits. They will enter Chris Caldwell's The Largest Known Primes Database ranked 1st for twins. This is PrimeGrid's third record twin.

The discovery was made by Timothy D. Winslow of the United States using an Intel Core i7 920 @ 2.67GHz with 8 GB RAM running Windows 7 Ultimate. This computer, using LLR, took 9 minutes and 21 seconds to complete the primality tests of both primes. Timothy is a member of The Knights Who Say Ni! team.

The prime was verified on 26 Dec 2011 1:58:19 UTC, by Brage E. Elliott of the United States. For more details, please see the official announcement.

2011-12-26: World Record Twin Primes Found!

It appears that one lucky cruncher has received a very nice Christmas gift. Twin primes have been returned to the server and verified. They were found in the Sophie Germain Prime Search and are almost twice the size of the current record. This is an incredible accomplishment!

We are awaiting contact from the appropriate users. Stay tuned for more details. :)

2011-12-22: The Winter Solstice Challenge - Final

The Winter Solstice is here!!! The yule log, filled with factors, is making for a very bright night. This has been a very successful Challenge not only for PrimeGrid but also for the entire Riesel prime search community (benefactors of the k*2^n-1 that's also sieved). Once again, a new single day record was set during the final Challenge of the year. A hearty thanks and a warm appreciation for all those involved.

Over 2.86P of sieve work was crunched in ~318K tasks resulting in just over 1B cobblestones awarded. This is again a continuing legacy for Ken Brazier's tpsieve* port to the GPU. (*originally developed by Geoff Reynolds in collaboration with Ken Brazier)

Congratulations to Sicituradastra. as the top team and STE\/E as the top individual. For more stats and information, please see this forum post.

This concludes PrimeGrid's 2011 Challenge Series. Overall final results will be posted in a couple of days. Thank you to everyone who participated this year. We wish you a Happy Holidays and hope to see you next year!

2011-12-21: The Winter Solstice Challenge - 12 hrs remaining

The Solstice is soon upon us. Bundle up tight as it's going to be a long Winter's night. 12 hours remain in the Challenge. Time to round up all those factors, combine them into one HUGE yule log, and toss it into the fire.

The Winter Solstice arrives at 05:30 UTC 22 December 2011. Get your factors in by then. :)

2011-12-18: The Winter Solstice Challenge in 24 hours

The Solstice draws near and so does the start of the Winter Festival. Come one, come all and warm yourselves by the Solstice fires. PrimeGrid's 2011 Challenge series ends with a 3 day (19-22 Dec) Challenge on the PPS (Sieve) application.

For more information, please see this forum thread.

2011-12-16: The Winter Solstice Challenge in 3 days

The Solstice fires are currently being constructed. Foraging through the DB, we're gathering all the "cast off" factors and adding them to the stack. Come join the winter festival on the 19th as we celebrate the upcoming Solstice. Find your own factors and toss them into the fire.

A 3 day (19-22 Dec) Challenge is being offered on the PPS (Sieve) application. For more information, please see this forum thread.

2011-12-13: The Winter Solstice Challenge in 6 days

For those of us in the Northern Hemisphere, the full force of Winter is soon here. Please come join us in observing one of Nature's way-points...the Winter Solstice. A 3 day (19-22 Dec) Winter Festival/Challenge is being offered on the PPS (Sieve) application. 32 & 64 bit builds are available for Mac, Linux, and Windows as well as CUDA/ATI (OpenCL) for the GPU.

This will conclude PrimeGrid's 2011 Challenge series. For more information, please see this forum thread.

2011-12-07: GFN Prime Search Sieving

It has been a lukewarm response to the re-start of GFN sieving. This sieve will support 3 new N's in the GFN prime search (1048576, 2097152, 4194304). If you have Windows 64 bit and would like to put it to good use in a specialized sieve (one of which might eventually produce the world's largest prime), then please review these instructions.

This manual sieve is located in the Project Staging Area. It's a simple and straight forward process. For more details, please see this post.

2011-11-28: The March to the Solstice

Come join the March to the Solstice (24 Nov - 19 Dec). We'll be pushing PPS (LLR) as far along as possible before the final Challenge of the year, the Winter Solstice Challenge (19 Dec - 22 Dec). We have established intermediate goals for PPS (LLR) and are within striking distance of completing them by the end of year 2011.

This by no means is a "walk in the park". :) It will take a concentrated and sustained effort to reach these goals. For more details, please see this post.

2011-11-19: World Record Generalized Fermat Prime

On 19 Nov 2011 14:03:58, PrimeGrid's PRPNet found the largest known Generalized Fermat mega prime: 75898^524288+1

The prime is 2,558,647 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat Primes and 13th overall. This is the first prime found at N=524288.

The discovery was made by Michael Goetz of the United States using an NVIDIA GeForce GTX 460 in an Intel Core2 Q6600 @ 2.4GHz system with 8GB RAM, running 64 bit Windows 7. The GPU took just under 5 hours to probable prime (PRP) test with GeneferCUDA. The CPU completed the primality test using pfgw64 in a little over 8 days! Michael is a member of the SETI.USA team.

For more details, please see the official announcement.

2011-11-17: The Leonids Challenge in 24 hours

Come see if you can catch a "falling star" in the Leonids meteor shower Challenge. A 5 day Challenge is being offered on the 321 Prime Search (LLR) project. For more information, please see this forum post.

2011-11-15: The Leonids Challenge in 3 days

In 3 days, the Leonids Challenge will begin. Come watch the "falling stars" and see if you can snag a 321 Mega Prime. A 5 day (18-23 November) Challenge is being offered on the 321 Prime Search (LLR) application. For more information, please see this forum post.

2011-11-13: The Leonids Challenge in 5 days

In 5 days, the Leonids Challenge will begin. Come watch the "falling stars" and hopefully find a rare 321 prime. A 5 day (18-23 November) Challenge is being offered on 321 Prime Search (LLR) application. For more information, please see this forum post.

2011-11-11: LLR v3.8.6 released

After experiencing some erratic behavior from several new hosts, specifically the AMD FX(tm)-8120 Eight-Core Processor, we have updated LLR from v3.8.4 to v3.8.6. This latest version uses GWNUM v26.6, and it appears to have solved the problem.

We expect high bandwidth usage over the next several hours as LLR v3.8.6 is downloaded for Linux, Windows, and Mac OS's.

2011-11-06: World Record Generalized Fermat Prime

On 29 Oct 2011 11:31:47 UTC, PrimeGrid?s PRPNet found the largest known Generalized Fermat Prime: 361658^262144+1

The mega prime is 1,457,075 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat Primes and 24th overall.

The discovery was made by Michel Johnson of Germany using an NVIDIA GeForce GTX 550 Ti in an AMD PHENOM II X6 1100T @ 3.3GHz system with 4GB RAM, running 32 bit Windows XP. This GPU took about 1 hour and 45 minutes to probable prime (PRP) test with GenefCUDA. (NOTE: This is the first prime found by geneferCUDA!) Michel is a member of the SETI.Germany team.

The prime was confirmed in 50 hours and 40 minutes using pfgw64 on an Intel Xeon 5410 @ 2.33GHz with 16GB RAM, running Windows Server 2003 x64.

For more details, please see the official announcement.

2011-10-20: SGS single primes reaching the end of the Top 5000 list

The single primes as a byproduct from the Sophie Germain Prime Search are reaching the end of their stay in the Top 5000 list. There's roughly 10-14 days left until they will no longer enter the list. This does not affect the overall search as the goal remains to find a Sophie Germain prime and/or a twin prime.

If you're still looking for your first reportable SGS single prime, now's the time to get it. The elusive Sophie Germain and twin primes are still at large so there remains a chance at finding one of them as well. :)

To run this project, simply select "Sophie Germain Prime Search (LLR)" on your PrimeGrid preferences page.

2011-10-01: October's PRPNet Project

The dual Sierpinski problem (Five or Bust) is PrimeGrid's PRPNet project of the month for October. The goal will be to complete the double check effort before the end of the month.

The project will run from 1 October to 31 October (hopefully it will end sooner). It will be a great opportunity to be part of worthy cause in closing out the dual Sierpinski problem. Feel free to stop by after the Equinox Challenge is complete. For more information, please see this forum post.

2011-10-01: The Equinox Challenge Update

Just over a week into the 13 day Equinox Challenge and the competition is heating up. A lot of back and forth going on by both teams and individuals in some very tight races. It's not too late to get another couple of WU's completed before the end (06 Oct 2011 18:00 UTC). Sadly, no luck with finding a Woodall prime yet.

For more information on joining the Challenge, please see this forum post.

2011-09-22: The Equinox Challenge in 22 hours

A 13 day Challenge marathon on the Woodall Prime Search project approaches in just 22 hours. This Challenge is PrimeGrid's longest of the year and the Challenge points the highest. Come join us on the autumnal equinox, 23 Sep 2011 18:00 UTC, and see how many tasks you can return by 06 Oct 2011 18:00 UTC.

For more information, please see this forum post.

2011-09-19: The Equinox Challenge in 5 days

PrimeGrid's Challenge series continues with the "Equinox Challenge". Come join us as we usher in the fall and cooler temperatures with a 13 day marathon on the Woodall Prime Search project. The challenge will begin on the autumnal equinox, 23 Sep 2011 18:00 UTC, and end 06 Oct 2011 18:00 UTC.

For more information, please see this forum post.

2011-09-12: Prime

Congratulations to Grzegorz Granowski (Grzegorz Granowski) of Poland, the discoverer of PrimeGrid's 8th Prime Fermat Divisor in the Proth Prime Search project: 25*2^2141884+1 Divides F(2141872). This is the 292nd known divisor and the 9th found in 2011. Grzegorz is a member of the Polish National Team.

For more details, please see the official announcement (coming soon).

2011-09-12: Prime Fermat Divisor found

Congratulations to Grzegorz Granowski (Grzegorz Granowski) of Poland, the discoverer of PrimeGrid's 8th Prime Fermat Divisor in the Proth Prime Search project: 25*2^2141884+1 Divides F(2141872). This is the 292nd known divisor and the 9th found in 2011. Grzegorz is a member of the Polish National Team.

For more details, please see the official announcement.

2011-08-24: PRPnet issues

Because of a router failure some PRPnet servers for Project Staging Area are not accessible. None of the BOINC services are affected and all are running fine.

We are trying to work around the problem by routing network requests around because the hardware isn't accessible at the moment and can't be rebooted and/or replaced. Because of this you may see some connection errors in the nearest future.

Update 19:10: PRPnet requests are now being routed around the failed router. PRPnet IP address has changed, so it will take time for DNS to synchronize - if you still can't connect, please give it some more time.

2011-08-20: The Dog Days of Summer Challenge

The Dog Days are here! In just 6 days, PrimeGrid's Challenge series continues with the Dog Days of Summer Challenge (26-28 August). Please come join us for a 2 day Challenge on PrimeGrid's Proth Prime Search (LLR) application. Builds are available for Linux, Mac and Windows.

For more information, please see this forum thread.

2011-07-10: Prime Fermat Divisor found

Congratulations to Peter Doggart (Hammeh) of the United Kingdom, the discoverer of PrimeGrid's 7th Prime Fermat Divisor in the Proth Prime Search project: 4479*2^226618+1 Divides F(226614). This is the 291st known divisor and the 8th found in 2011. Peter is a member of PrimeSearchTeam.

For more details, please see the official announcement.

2011-07-02: Prime Fermat Divisor found

Congratulations to Mark Doom (Mark Doom) of the United States, the discoverer of PrimeGrid's sixth Prime Fermat Divisor in the Proth Prime Search project: 3771*2^221676+1 Divides F(221670). This is the 289th known divisor and the 6th found in 2011. Mark is a member of team Aggie The Pew.

For more details, please see the official announcement.

2011-06-23: Prime Fermat Divisor found

Congratulations to Dirk D'huyvetters (Dirk) of Belgium, the discoverer of PrimeGrid's fifth Prime Fermat Divisor in the Proth Prime Search project: 7333*2^138560+1 Divides F(138557). This is the 288th known divisor and the 5th found in 2011.

For more details, please see the official announcement.

2011-06-23: World Record Prime Fermat Divisor

Congratulations to Scott Brown (Scott Brown) of the United States, the discoverer of a World Record Prime Fermat Divisor: 9*2^2543551+1 Divides F(2543548).

The prime is 765,687 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Prime Fermat Divisors and 57th overall.

This is PrimeGrid's 1st found prime Fermat divisor since 2009 and 4th overall. This is the 287th known divisor and the 4th found in 2011.

For more details, please see the official announcement.

2011-06-21: PrimeGrid's Birthday/Summer Solstice Challenge - Final

The Summer Solstice has arrived in the Northern Hemisphere. We hope everyone enjoys this longest day of the year...and for you Southern Hemisphere folks, we hope you kept warm. :)

The Cullen/Woodall (Sieve) reached an incomplete depth of over 566T. Over 30T of sieve work was crunched in 251K tasks resulting in over 91.5M cobblestones awarded.

Congratulations to Sicituradastra. as the top team and Ross* as the top individual. For more stats and information, please see this forum post.

Thank you again to everyone. We appreciate your participation and hope you had fun! Have a wonderful summer and we look forward to seeing you in a couple months at the next Challenge - The Dog Days of Summer Challenge - 26-28 August - 48 hours on the PPS (LLR) application! Come take a break from the Dog Days and cool off with a few primes. It's a GREAT opportunity for you to find a Top 5000 Prime. :)

2011-06-18: PrimeGrid's Birthday/Summer Solstice Challenge in 2 days

PrimeGrid's Challenge series continues with the "Birthday/Summer Solstice Challenge". Come join us as we celebrate PrimeGrid's 6th birthday. A 24 hour Challenge is being offered on the Cullen/Woodall (Sieve) application. The celebration will culminate in the ancient observation of the Summer Solstice, 21 June!

For more information, please see this forum post.

2011-06-13: World Record Factorial Prime

On 11 June 2011, PrimeGrid?s PRPNet found the largest known Factorial prime: 110059!+1

The prime is 507,082 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Factorial primes and 130th overall.

The discovery was made by Peter Doggart (Hammeh) of the United Kingdom using an AMD Phenom 9600 X4 @ 2.3GHz with 3GB RAM, running 32 bit Windows 7. This computer took just under 57 hours and 46 minutes to complete the primality test using pfgw. Peter is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2011-06-01: Mega Prime found for The Riesel Problem (Dรฉjร  vu Dรฉjร  vu)

On 31 May 2011 20:08:26 UTC, PrimeGrid?s The Riesel Problem project eliminated k=353159 by finding the mega prime: 353159*2^4331116-1

The prime is 1,303,802 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 25th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's 7th elimination. 57 k's now remain.

The discovery was made by Jaakko Reinman (sqweeser) of Finland using an Intel Core2 Quad Q9550 @ 2.83GHz with 4 GB RAM running Linux. This computer took just over 8 hours and 9 minutes to complete the primality test using LLR. Jaakko is a member of the BOINC@Finland team.

The prime was verified on 1 Jun 2011 4:05:40 UTC, by Grzegorz Granowski (Grzegorz Granowski) of Poland. For more details, please see the official announcement.

2011-05-29: Mega Prime found for The Riesel Problem

On 26 May 2011 11:08:52 UTC, PrimeGrid?s The Riesel Problem project eliminated k=141941 by finding the mega prime: 141941*2^4299438-1

The prime is 1,294,265 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 25th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's sixth elimination. 58 k's now remain.

The discovery was made by Scott Brown (Scott Brown) of the United States using an Intel Core2 Duo E8400 @ 3.0GHz with 4 GB RAM running Windows 7. This computer took just over 7 hours and 25 minutes to complete the primality test using LLR. Scott is a member of the Duke University team.

The prime was verified on 28 May 2011 23:08:20 UTC, by Piotr M. Zalewski (Piotr M. Zalewski) of Poland. For more details, please see the official announcement.

2011-05-13: Mega Prime found for The Riesel Problem (D?j? vu)

Remarkably, another mega prime has been found during the Cinco de Mayo Challenge.

On 8 May 2011 15:43:27 UTC UTC, PrimeGrid?s The Riesel Problem project eliminated k=415267 by finding the mega prime: 415267*2^3771929-1

The prime is 1,135,470 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 29th overall. This is the 2nd largest prime found in The Riesel Problem and PrimeGrid's fifth elimination. 59 k's now remain.

The discovery was made by Alexey Tarasov (Alexus78) of the Ukraine using an Intel Core2 Duo E6550 @ 2.33GHz with 1 GB RAM running Windows XP Professional. This computer took just over 10 hours and 18 minutes to complete the primality test using LLR. Alexey is a member of the Ukraine team.

For more details, please see the official announcement.

2011-05-11: Mega Prime found for The Riesel Problem

On 8 May 2011 7:29:52 UTC, PrimeGrid?s The Riesel Problem project eliminated k=123547 by finding the Mega prime: 123547*2^3804809-1

The prime is 1,145,367 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 28th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's fourth elimination. 60 k's now remain.

The discovery was made by Jakub ?uszczek (..:: Thor ::..) of Poland using an Intel Core i5 2500 @ 3.3GHz with 8 GB RAM running Windows 7 Home Premium x64. This computer took just over 4 hours and 35 minutes to complete the primality test using LLR. Jakub is a member of the Polish National Team.

For more details, please see the official announcement.

2011-05-04: The Cinco de Mayo Challenge in less than 3*2^3 hours

Come join us for the 5th day of the 5th month celebration. A 2^3 day Challenge is being offered on PrimeGrid's "The Riesel Problem" (LLR) application?ends on the 13th. There remains 61 k's in The Riesel Problem for which no primes have been found.

For more information, please see this forum post.

2011-05-02: BOINC Pentathlon

SETI.Germany is hosting the 2nd annual BOINC Pentathlon where all BOINC-Teams are invited to participate. This year, PrimeGrid has been chosen as the second of five disciplines. The Pentathlon will focus on PrimeGrid's GPU projects from 8 May 2011 to 13 May 2011.

For more information on this special event and to see the other projects selected, please visit BOINC Pentathlon Welcome page.

2011-04-26: The Cinco de Mayo Challenge in 3^2 days

In 3^2 days, come join us for the 5th day of the 5th month celebration. A 2^3 day Challenge is being offered on PrimeGrid's "The Riesel Problem" (LLR) application?ends on the 13th. That's a lot of prime numbers in the first 2 sentences. :) Let's continue the trend and find some primes during the Challenge. There remains 61 k's in The Riesel Problem for which no primes have been found.

For more information, please see this forum post.

2011-04-20: April's PRPNet Project - 5oB home stretch

Two thirds of the way through the month and we're in the home stretch. The 5oB double check is turning out to be like a good old fashioned tractor pull. The closer we get to the finish, the harder the task becomes. Now more that ever we need additional help to help stave off the decline in our daily rate?which has seen seven straight days of decline.

The higher numbers are starting to get the better of us and the naysayers are beginning to weigh down the sled. Let's throw some extra power on this and knock the naysayers off. :)

Please keep spreading the word. We still need more support to reach the goals. For more information, see this forum post.

2011-04-17: Subproject completion - 321 Prime Search (Sieve)

321 Prime Search (Sieve) subproject has reached the "optimal zone" and will be suspended on 22 April 2011. This means that no more work for 321 Prime Search (Sieve) will be added after 22nd, but outstanding work will be allowed to complete. 321 Prime Search (LLR) will not be affected and will continue running.

Once the work is depleted, project preferences will be automatically changed for people who have selected only 321 Prime Search in their preferences. Default subprojects will be selected, but you may wish to proactively choose a subproject or two.

For people fighting for a badge this may be a good opportunity to push if you are lacking just a few credits.

2011-04-15: April's PRPNet Project - 5oB

Half way through the month and steady progress continues. We are certainly making the naysayers sweat a little. The first goal is definitely within reach. A HUGE thanks to everyone who has answered the call for help. Let's keep the pressure up!!!

Please keep spreading the word. We still need more support to reach the other two goals...tell a teammate or two or three. :) For more information, see this forum post.

2011-04-12: Mega Prime found for The Riesel Problem

On 5 Apr 2011 7:13:12 UTC, PrimeGrid?s The Riesel Problem project eliminated k=65531 by finding the Mega prime: 65531*2^3629342-1

The prime is 1,092,546 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 29th overall. This is the largest prime found in The Riesel Problem and PrimeGrid's third elimination. 61 k's now remain.

The discovery was made by Adrian Schori of Switzerland using an Intel Core i5 750 @ 2.67GHz with 4 GB RAM running Mac OS X. This computer took just over 5 hours and 12 minutes to complete the primality test using LLR. Adrian is a member of SwissTeam.NET.

For more details, please see the official announcement.

2011-04-10: April's PRPNet Project - 5oB

A third of the way through the month and our effort to help out the successful "Five or Bust" project is making steady progress.

If you are in search for your PSA badge (or upgrade the one you have), now is a good opportunity to get that done as well as give to a worthy cause. :) PSA credit is available. If you are new to PRPNet, individualized "pre-set" packages can be made where all you'll have to do is download, double click a couple of times and be quickly contributing to the project.

We have updated goals for the month. Please see if you can help us reach them. For more information, see this forum post.

2011-04-09: The Marie-Sophie Germain Challenge - Final

After a relatively quick "clean-up", the results are final. What an excellent turnout for the Challenge. Over 120 single primes were returned during the Challenge. Unfortunately, no luck with finding a Sophie Germain or twin prime.

Over 1.3M tasks were completed resulting in over 11.3M Challenge points awarded. Congratulations to Ukraine as the top team and Alexus78 as the top individual. For more stats and information, please see this forum post.

Thank you again to everyone. We appreciate your participation and hope to see you at the Cinco de Mayo Challenge. Come join us 5-13 May for an 8 day celebration on The Riesel Problem (LLR) application! Currently, there are 61 k's remaining that need to be eliminated.

2011-04-01: The Marie-Sophie Germain Challenge in 3 hours

Come join us as we pay tribute to Marie-Sophie Germain with a 2 day (1-3 April) Challenge on the Sophie Germain Prime Search project.

For more information, please see this forum post.

2011-03-30: The Marie-Sophie Germain Challenge in 2 days

Marie-Sophie Germain was born on April 1, 1776, in Paris, France. She was an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki) Come join us as we pay tribute to her with a 2 day (1-3 April) Challenge on the Sophie Germain Prime Search project.

For more information, please see this forum post.

2011-03-12: Planned maintenance on Monday

We are planning a short downtime on Monday to install additional hardware and reorganize network in the server rack. You may wish to increase work cache slightly if you are running with a very low cache size.

[update 15:25UTC] Maintenance has been completed successfully.

2011-03-09: Generalized Fermat Mega Prime

On 08 Mar 2011 10:35:34 UTC, PrimeGrid's PRPNet found a Generalized Fermat mega prime: 40734^262144+1

The prime is 1,208,473 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat Primes and 26th overall.

The discovery was made by Senji Yamashita of Japan using an Intel Core 2 Quad Q9450 @ 2.66GHz with 2GB RAM, running Windows 7 Professional 64bit. This computer took 4 hours and 29 minutes to complete the primality test using pfgw64. Senji is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2011-03-01: World Record 321 Prime

On 21 Feb 2011 21:45:32 UTC, PrimeGrid?s 321 Prime Search found another Mega Prime: 3*2^7033641+1

The prime is 2,117,338 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 14th overall. This is the second mega prime and the largest for the 3*2^n+1 form. It is also the second largest found mega prime using LLR and PrimeGrid's 10th overall mega prime.

The discovery was made by Michael Herder using an Intel Core i7 920 @ 2.67GHz with 6 GB RAM running Windows 7 Ultimate x64. This computer took just over 17 hours and 24 minutes to complete the primality test using LLR. Michael is a member of the BOINCstats team.

For more details, please see the official announcement.

2011-03-01: World Maths Day Challenge in 15 hours

The World Maths Day games are in full swing. Head over there to test your math skills. But don't forget to check back here in less than 15 hours. A 24 hour Challenge is being offered on PrimeGrid's The Riesel Problem (Sieve).

For more information, please see this forum post.

2011-02-26: World Maths Day Challenge in 3 days

Time to dust off the cobwebs and start recalling all your math knowledge. PrimeGrid's 2011 Challenge series continues with the "World Maths Day Challenge". Come join the competition here as well as at the World Maths Day games. World Maths Day begins earlier than the Challenge so head there now to register before it's too late.

For more information, please see this forum post.

2011-02-25: World Record Generalized Woodall Prime

On 24 Feb 2011, 17:27:31 UTC, PrimeGrid?s PRPNet found the largest known generalized Woodall prime:

404882*43^404882-1

The prime is 661,368 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for generalized Woodall primes and 71st overall.

The discovery was made by Ricky L. Hubbard of the United States using an AMD Athlon II X4 635 @ 2.90GHz with 8GB RAM, running Windows 7. This computer took about 4 hours and 15 minutes to complete the probable prime test using pfgw64 and a little over 30 hours 3 minutes to complete the primality test again using pfgw64. Ricky is a member of the AMD Users Team.

For more details, please see the official announcement.

2011-02-22: World Maths Day Challenge

PrimeGrid's 2011 Challenge Series continues with the "World Maths Day Challenge". World Maths Day is a day to promote numeracy through games and competition. It has been created for students aged 4 - 18 years with the addition for the first time this year of an adult category, ages 19 to 119. Compete against others around the world in live games of mental arithmetic.

In honor of World Maths Day, PrimeGrid is offering 24 Challenge (1-2 March) on The Riesel Problem (Sieve) application. For more information, please see this forum post.

p.s. Please spread the word about World Maths Day. Their goal this year is to achieve 1 billion correct answers.

2011-02-10: World Record Generalized Fermat Prime

On 8 Feb 2011 09:38:57 UTC, PrimeGrid?s PRPNet found the largest known Generalized Fermat Prime: 145310^262144+1

The mega prime is 1,353,265 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Generalized Fermat Primes and 23rd overall.

The discovery was made by Ricky L Hubbard of the United States using an AMD PHENOM II X6 1090t @ 3.2GHz with 8GB RAM, running Windows 7. This computer took about 11 hours to probable prime (PRP) test with GenefX64 and 48 hours and 15 minutes to complete the primality test using pfgw64. Ricky is a member of the AMD Users team.

For more details, please see the official announcement.

2011-02-08: State of the validator after the challenge

Because of the massive amount of work that we received during the challenge, we have a big backlog for the validator to process. While it may seem that validation has stopped, it is simply not true, and validator is working through the backlog. This backlog also causes problems displaying pending credit page for some users.

We estimate that the valitator will catch up in less than a week. Until then credit for newly reported results may be slightly delayed.

2011-02-06: The Year of the Rabbit Challenge Preliminary results

What an amazing amount of work completed and a ton of primes found. Although the validator was overwhelmed early on, the server held up to the stress (fortunately this did not affect scoring).

Once again, it was exciting to see the top teams go neck and neck to the wire. This Challenge will set several records. We'll need a few days to process the data. A lot of xGFN testing is left to do on the found primes so expect them to roll out over the next few days. :)

The Challenge is over and now the "clean up" process begins. We are expecting roughly a week but hoping for less.

Official results are most likely less than a week away, but for preliminary results, please see this forum post. Thank you to everyone who participated.

2011-02-03: The Year of the Rabbit Challenge has begun

The Challenge has begun, but first you must answer these three questions before you cross the bridge of primes. What is your name? What is your quest? What is name of the prime where k=n?

For more information about the Challenge, please see this forum post. Best of Luck to everyone!

2011-02-03: The Year of the Rabbit Challenge begins

The Challenge has begun, but first you must answer these three questions before you cross the bridge of primes. What is your name? What is your quest? What is the name of the prime where k=n?

For more information about the Challenge, please see this forum post. Best of Luck to everyone!

2011-02-02: The Year of the Rabbit Challenge in 24 hours

In the immortal words of Tim the Enchanter, "I warned you! But did you listen to me? Oh, no, you knew it all, didn't you? Oh, it's just a harmless little bunny, isn't it?" Watch out for those primes...some of them can be quite hard to tame. Beware of the ones with nasty big pointy teeth. :)

A 3 day (3-6 Feb) Year of the Rabbit Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. For more information, please see this forum post.

2011-02-01: The Tour de Primes begins!

Come join us in laid-back competition in tribute to the number 2...the first prime and the only even prime. The prizes are simple colored jerseys . Yellow for the most primes, Green for the highest prime score, and Checkered for the most primes on 5 Feb. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2011.

2011-01-31: The Year of the Rabbit Challenge in 3 days

"Thou shalt count to three, no more, no less. Three shalt be the number thou shalt count, and the number of the counting shalt be three. Four shalt thou not count, nor either count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then lobbest thou thy Holy Host of Antioch towards thou task, who being naughty in my sight, shall snuff it." ;)

A 3 day (3-6 Feb) Year of the Rabbit Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. For more information, please see this forum post.

2011-01-29: The Year of the Rabbit Challenge

You know what they say about rabbits? Well, we hope it's the same for primes during this Challenge. :D Come join us as we propagate the Top 5000 list with a litter of kits...I mean, a bunch of primes! It's a GREAT opportunity for you to find a prime for yourself! Who knows, there may even be the rare Fermat number divisor. :)

A 3 day (3-6 Feb) Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. For more information, please this forum post.

2011-01-27: Tour de Primes 2011

February is just a few days away which means it is almost time for the 3rd annual Tour de Primes. 2 is the first prime number...and the only even one. Therefore, we have declared February, the 2nd month, as prime month.

We're offering a small informal competition in tribute to this unique prime number. There are no points to be gained or awards to be won...just a simple colored jersey (Yellow, Green, and Checkered) at the end of the month. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2011.

2011-01-18: Mega Prime found for The Riesel Problem

On 14 Jan 2011 9:03:07 UTC, PrimeGrid?s The Riesel Problem project eliminated k=428639 by finding the Mega prime: 428639*2^3506452-1

The prime is 1,055,553 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 29th overall. This is the 2nd largest prime found in The Riesel Problem and PrimeGrid's second elimination in 2 months. 62 k's now remain.

The discovery was made by Brett Melvold of Australia using an Intel i7 920 @ 2.67GHz with 6GB RAM, running Windows 7. This computer took 11 hours and 13 minutes to complete the primality test using LLR. Brett is a member of the BOINC@AUSTRALIA team.

For more details, please see the official announcement.

2011-01-17: GFN PRPNet Challenge - Results

The GFN Prime Search PRPNet Challenge was a nice success. Congratulations to Senji Yamashita (s-yama) as the top individual scorer. Additional congratulations goes out to Amy Chambers (Buckeye74) who found PrimeGrid's first GFN prime in this search. This prime was quickly followed less than an hour and a half later by another prime discovered by Ross Goudie (Ross*). The goal of finding at least one GFN prime was achieved. For complete scores, please see here.

The search continues with the month long goals of finding a prime at each of the following N's: 65536, 262144, 524288. For more information, please see the GFN Prime Search. BTW, the GPU really shines at the higher N's. :)

2011-01-09: January's PRPNet Challenge Project on GFN

Pierre de Fermat (1601-1665) is often called the "Prince of Amateurs." It is in his honor that the first PRPNet Challenge of 2011 is on the Generalized Fermat Number (GFN) Prime Search. A 3 day Challenge is being offered starting 12 January 2011 00:00 UTC on PrimeGrid's PRPNet. NOTE: PrimeGrid's BOINC Challenge series doesn't start until 3 February 2011.

With the breakthrough of porting Genefer 2.2.0 to the GPU (CUDA), the search has become much more attractive. Testing times for the higher N's have been drastically reduced. NOTE: GPU app requires double precision support. Come be the first at PrimeGrid to report a Top 5000 prime found by a GPU.

For more information, please see this forum thread.

2011-01-07: Sierpinski/Riesel Base 5 Project

With the success of The last 10 Days of 2010 PRPNet Challenge, we are happy to announce that a collaboration has been formed between PrimeGrid and the Sierpinski/Riesel Base 5 Project. This is a combination of the SoB and TRP projects, except for the base of 5 instead of 2.

SR5 will enter PrimeGrid's Project Staging Area. The goal will be to make 2011 the best year of the project in terms of work completed. For more information about the SR5 Project, please see this forum post.

2011-01-01: Happy New Year 2011!

Happy New Year 2011...a prime number year! Here's a little trivia from Prime Curios!:2011 - Two thousand "eleven" is the sum of 11 consecutive primes. Can you find them? [Post]

2010-12-31: 2010 Challenge Series Final Rankings

PrimeGrid's 2010 Challenge Series is final. This year saw tremendous growth as well as tougher competition. The expansion of "scoring positions" was a nice success and allowed more users and teams to participate in the rankings.

Congratulations to SETI.USA as the top team and Mr. Hankey as the top individual. They are the winners of PrimeGrid's 2010 Challenge Series. For complete, extended rankings please see: Individuals | Teams

As always, thank you for your help and support. We continue to be humbled by your participation. None of this is possible without YOU! :) Have a safe and happy Holiday season. See you next year for PrimeGrid's 2011 Challenge Series!

2010-12-31: Unexpected downtime

We had some downtime because of database issues. They should be resolved and the work should be flowing fine now.

2010-12-31: SR5 PRPNet Challenge - fourth and fifth prime!

The stars must have aligned today as two SR5 primes were found in the Challenge. One by Murphy Babb (his second) of the United States and one by Sascha Beat Dinkel of Switzerland. Murphy's prime (3938*5^558032-1) is 390,052 digits and ranks 3rd for SR5 primes and 218th overall. Sascha's prime (151026*5^559670-1) is 391,198 digits and ranks 2nd for SR5 primes and 216th overall.

This is a GREAT way to lead into the final 24 hours of the Challenge. Looks like we've even hit the 5 primes request. What more is there to ask for now??? :D How about an SR5 prime for everyone participating? Is that too lofty of a goal?

If you are interested in participating, please see the Last 10 Days of 2010 PRPNet Challenge post.

2010-12-29: SR5 PRPNet Challenge - third prime!

Matthew Poulter of the United Kingdom has found the third prime of the SR5 PRPNet Challenge. It is 385,673 digits and ranks 2nd for SR5 primes and 224th overall in the Top 5000 primes database!

105782*5^551766-1

Now that 2010 has become the best year of the project, let's see how far we can push it. With just over 2 days left in the Challenge, we have an opportunity to find a couple more primes and make 2010 head and shoulders above the rest.

If you are interested in participating, please see the Last 10 Days of 2010 PRPNet Challenge post.

2010-12-27: SR5 PRPNet Challenge - second prime!

Murphy Babb of the United States has found the second prime of the SR5 PRPNet Challenge. And what a nice one it is...coming in ranked 4th for SR5 primes and 265th overall in Top 5000 primes database!

183916*5^519597-1

This prime marks a nice milestone for the SR5 project. Removing k=183916 brings the sieve file to less than 3M terms remaining (to n=2M). The current sieve file has 2,982,533 terms in 181 sequences.

Only one more prime is needed to make 2010 the best year of the SR5 project in regards to prime score. If you are interested in participating, please see the Last 10 Days of 2010 PRPNet Challenge post.

2010-12-26: SR5 PRPNet Challenge

Micha? Gasewicz of Poland has found the first prime of the SR5 PRPNet Challenge. Yes, the same "lucky" person who found the World Record Primorial prime last week...even with the same computer!!! This is most definitely a good holiday season for him. :)

53542*5^515155-1

Only two more primes are needed to make 2010 the best year of the SR5 project in regards to prime score. If you are interested in participating, please see the Last 10 Days of 2010 PRPNet Challenge post.

NOTE: Anyone needing assistance in joining the PRPNet Challenge, an individualized package can be created for you. All you'd have to do is download, unzip, and double click a few times and...PRPNet will do the rest. :) Builds are available for Linux, Mac, and Windows.

2010-12-24: World Record Primorial Prime

On 20 Dec 2010, 08:05:22 UTC, PrimeGrid?s PRPNet found the largest known Primorial prime: 843301#-1

The prime is 365,851 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Primorial primes and 260th overall.

The discovery was made by Micha? Gasewicz of Poland using an Intel dual Xeon E5520 @ 2.27GHz with 12GB RAM, running 64 bit Linux. This computer took about 71 hours and 20 minutes to complete the primality test using pfgw x64. Micha? is a member of the BOINC@Poland team.

For more details, please see the official announcement.

2010-12-22: The Winter Solstice Challenge - Final

The Winter Solstice is here!!! The solstice fires are the brightest they have ever been at PrimeGrid. The fuel came from an unprecedented amount of factors found. This Challenge benefited not only PrimeGrid's Proth Prime Search project but also the entire Riesel prime search community. A wonderful holiday gift to all those involved. :)

1.3P of sieve work was crunched in 434K tasks. A HUMONGOUS sieve that would have been impossible to do without Ken Brazier's help. A special thanks to him for his modifications to tpsieve as well as his port to GPU's.

Congratulations to Sicituradastra. as the top team and Steve* as the top individual. Remember, the top 100 individual and top 50 team places earn points for this Challenge. For more stats and information, please see this forum post.

This concludes PrimeGrid's 2010 Challenge Series. Overall final results will be posted soon. Thank you to everyone who participated this year. We wish you a Happy Holidays and hope to see you next year!

2010-12-20: Primorial prime found in PRPNet

Tis the season to be merry!!! :) With last week's Factorial prime and today's Primorial prime, this holiday is shaping up to be quite generous.

The prime is only the 19th known p#-1 form and the 1st discovered in 18 years. It is the 1st found of either form (p#+1, p#-1) in over 9 years. Needless to say, this is exceptionally rare. It almost doubles the size of the previous record of 392113#+1 (169966 digits).

More details to come once the double check is complete.

2010-12-17: The Winter Solstice Challenge in 24 hours

Soon the winter festival will begin. Come warm yourself by the Solstice fires. PrimeGrid's Challenge series ends 2010 with a 3 day (18-21 Dec) Challenge on PPS (Sieve). 32&64 bit builds are available for Mac, Linux, and Windows as well as CUDA/ATI (OpenCL) for the GPU. For more information, please see this forum thread.

2010-12-15: The Winter Solstice Challenge in 3 days

PrimeGrid's Challenge series ends 2010 with the Winter Solstice Challenge. Please come join us in observing Nature's ending/beginning of a cycle...a Winter Festival on PrimeGrid's only GPU accessible project. A 3 day (18-21 Dec) Challenge is being offered on PPS (Sieve). 32&64 bit builds are available for Mac, Linux, and Windows as well as CUDA/ATI (OpenCL) for the GPU. For more information, please see this forum thread.

2010-12-15: Downtime

We are going to have a short downtime today at around 12:00 UTC to install additional memory for the database server. Both BOINC server and website will not be available at that time.

Update 14:00 UTC: maintenance has been completed, and we are now running with 16GB of available memory. We will continue tweaking MySQL, so you can still expect short downtimes.

2010-12-15: World Record Factorial Prime

On 14 Dec 2010 02:12:42 UTC, PrimeGrid?s PRPNet found the largest known Factorial prime: 103040!-1

The prime is 471,794 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Factorial primes and 136th overall.

The discovery was made by James Winskill of New Zealand using an Intel Core 2 Duo @ 2.13GHz with 2GB RAM, running 32 bit Windows XP. This computer took about 46 hours and 42 minutes to complete the primalty test with pfgw. James is a member of the PrimeSearchTeam.

For more details, please see the official announcement.

2010-12-13: LLR 3.8.4 released for all LLR projects

Over the weekend, LLR V3.8.4_final for Linux and Mac was released for all LLR projects. Windows is still waiting for a new wrapper. Most hosts should see from 15%-20% speed up in primality testing. This will be welcomed relief in the longer LLR projects (SoB, PSP, Cullen, Woodall, 321 & TRP). Good Luck!

LLR V3.8.4 from Jean Penne uses the final V26.4 gwnum code from George Woltman.

2010-12-03: Mega Prime found for The Riesel Problem

On 21 Nov 2010, 11:14:00 UTC, PrimeGrid?s The Riesel Problem project eliminated k=191249 by finding the Mega prime: 191249*2^3417696-1

The prime is 1,028,835 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 29th overall. This is the 2nd largest prime found in The Riesel Problem and the first k elimination in over 2 1/2 years. 63 k's now remain.

The discovery was made by Jonathan Pritchard of the United Kingdom using an AMD Phenom 9950 with 8GB RAM, running Windows 7. This computer took 7 hours and 31 minutes to complete the primality test using LLR. Jonathan is a member of the Turan@BOINC team.

For more details, please see the official announcement.

2010-12-01: Official release of tpsieve for PPS (Sieve)

PrimeGrid is excited to finally announce the official release of the tpsieve application in the PPS (Sieve) project. Linux, Mac, and Windows platforms for 32/64 bit are all supported as well as CUDA and OpenCL (ATI). Only Mac OpenCL is NOT currently available. Also, OpenCL requires an app_info file to run due to a scheduling request issue. However, we hope to have that problem resolved before the next Challenge (18-21 December). NOTE: Windows GPU users should update to .NET Framework 3.5.

tpsieve, based on Geoff Reynolds' original code, is a revolution to k*2^n+1/-1 sieving. Thanks in large part to Ken Brazier's updates and modifications to include simultaneous +1/-1 dat-less sieving as well as his ports to the GPU, tpsieve has changed the landscape of sieving and is now providing incredible support to the prime finding community.

Thank you Ken!!!

2010-11-29: The Leonids Challenge - Final

The results are final. What a splendid show for both the Leonids and the Challenge. Over 100 single primes were returned during the Challenge...greatly exceeding our expectation. Unfortunately, no luck with finding a Sophie Germain or twin prime.

719K tasks were completed resulting in over 6.1M Challenge points awarded. Congratulations to Team Norway as the top team and shanky123 as the top individual. For more stats and information, please see this forum post.

Thank you to everyone who participated!!! The final Challenge of 2010 is the Winter Solstice Challenge...come join us 18-21 December for 3 days on the Proth Prime Search (Sieve) application! As this year's only GPU application Challenge, it's sure to light the solstice fires!!!

2010-11-24: Prime found in The Riesel Problem!!!

The first prime in almost 2 1/2 years has been discovered for The Riesel Problem. More details to come after the primary finder has responded.

EDIT (29 Nov): Still awaiting contact from UserID 53352 (Jonathan Pritchard) of the Turan@BOINC team.

2010-11-19: The Leonids Challenge - Preliminary results

What a splendid show for both the Leonids and the Challenge. Once again, it was exciting to see the top 2 teams go neck and neck to the wire. Also, through the top 100 users, there are many positions separated by a single task. So far, no luck with finding a Sophie Germain or twin prime, but there were over 110 single primes returned during the Challenge...greatly exceeding our expectation.

The Challenge is over and now the "clean up" process begins. As a nice contrast to the Calendula Challenge, this one is shaping up to be very short.

Official results are most likely less than a week away, but for preliminary results, please see this forum post. Thank you to everyone who participated.

2010-11-16: The Leonids Challenge in 24 hours

Come join us at the peak of the Leonids for a 24 hour Challenge on the Sophie Germain Search (LLR) project. A Sophie Germain prime or even a twin prime may be waiting for you. ;) For more information, please see this forum post.

2010-11-14: The Leonids Challenge in 3 days

In 3 days, the Leonids Challenge will begin. Come watch the "falling stars" and hopefully find an elusive Sophie Germain prime or even a twin. A 24 hour (17-18 November) Challenge is being offered on The Sophie Germain Prime Search (LLR) application. For more information, please see this forum post.

2010-11-09: Proth Prime Search (Sieve)

The PPS (Sieve) will be pausing soon. When the current buffer empties and all outstanding work has been completed and validated, we'll be switching applications from ppsieve to tpsieve. This will allow for combined sieving of both +1 and -1 forms. For more information, please see this thread.

We hope to resume in less than a week. :)

2010-11-07: Preparing for Leonids II

This is a reminder that the 2nd test run is coming up today Sunday, 7 Nov 2010 18:00 UTC. Again it will be on the PPS (LLR) project. We'll be looking for a good balance between request handling speed and amount of tasks in memory. For this one, we'll need as many hosts as possible hitting the server at the start.

For results of the 1st test run, please see this post.

Thank you for your help! :)

2010-11-03: Test run results

The test run today was very productive. Thank you to everyone who participated. For details on what we learned, please see this post.

A new one hour test run has been scheduled for Sunday, 7 Nov 2010 18:00 UTC. Again it will be on the PPS (LLR) project. We'll be looking for a good balance between request handling speed and amount of tasks in memory. For this one, we'll need as many hosts as possible hitting the server at the start.

Thanks again for your help! :)

2010-11-01: Preparing for Leonids

The Leonids Challenge is coming up on 17 November 2010. The project is the Sophie Germain Prime Search which uses LLR to primality test candidates to find twin or Sophie Germain primes. With the new LLR v3.8.2 app, testing times have dropped in some cases as much as 20%. Therefore, while we still have time, we'd like to conduct test runs to evaluate server load.

The first run will be 3 November 2010 at 18:00. We'd like to run a 1 hr test on PPS (LLR) and produce as much stress as possible. We'll be monitoring load and making changes as necessary. If PPS (LLR) can run well under load, then SGS will as well with its longer tasks. For information, please see this forum thread.

2010-11-01: Work stats file move

Work stats file detailing user work done per subproject will be moved from /stats/ to /stats_work/ on Monday, November 8th. The new location is already live; everyone who is using the work stats file should update their scripts.

Note that the location change does not affect standard stats files.

2010-10-19: PSP/SoB (Sieve) nears end

The work buffer for PSP/SoB (Sieve) has reached 0. All that remains is work in progress. Since the deadline for these tasks is 7 days, we expect completion in a week or two depending on the number of expired tasks. Please see this post for updates on remaining tasks.

Suspension of the this sieve is a GREAT milestone. Congratulations to everyone who participated.

2010-10-08: The Calendula Challenge - Prelimiary results

For such a marathon of a Challenge, it was exciting to see the many close battles taking place. What's amazing is how close the top two spots were for both the team and individual categories. Although no one found the golden flower (PSP prime), excellent progress was made advancing the search.

The Challenge is over and now the "clean up" process begins. If you have the resources, please consider joining in the "clean up". We greatly appreciate any help. However, we fully understand the need/desire to "move on".

Official results are probably 6-8 weeks away, but for preliminary results, please see this forum post. Thank you to everyone who participated.

2010-10-08: The Calendula Challenge - Preliminary results

For such a marathon of a Challenge, it was exciting to see the many close battles taking place. What's amazing is how close the top two spots were for both the team and individual categories. Although no one found the golden flower (PSP prime), excellent progress was made advancing the search.

The Challenge is over and now the "clean up" process begins. If you have the resources, please consider joining in the "clean up". We greatly appreciate any help. However, we fully understand the need/desire to "move on".

Official results are probably 6-8 weeks away, but for preliminary results, please see this forum post. Thank you to everyone who participated.

2010-10-06: World Record Factorial Prime

On 04 Oct 2010, 15:01:15 UTC, PrimeGrid?s PRPNet found the largest known Factorial prime: 94550!-1

The prime is 429,390 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for Factorial primes and 155th overall.

The discovery was made by Dmitry Domanov of Russia using an Intel Intel Xeon E5310 @ 1.60GHz with 4GB RAM, running 32 bit Windows 2003 Server. This computer took 24 hours and 19 minutes to complete the prime test using pfgw. Dmitry is a member of Team Russia.

For more details, please see the official announcement.

2010-10-05: PSP/SoB (Sieve) to be suspended

13 October 2010 is approaching. This will be the last insertion date for PSP/SoB (Sieve) before it is suspended. Until then, the queue will be kept full for anyone wishing to complete their last effort on this project.

This is a major accomplishment for both the Prime Sierpinski Problem and the Seventeen or Bust projects. For more information, please see this forum thread.

2010-10-04: The Calendula Challenge - 3 days remain!

The flowers are starting to loose their fragrance and their petals are falling. Unfortunately, the long sought after golden flower has yet to bloom. :(

With 3 days remaining, it's time to start crunching those last tasks and emptying the cache. For those "moving on" after the Challenge AND have their last WU's processing, now would be a good time to set no new work. For more information, please see this forum post.

2010-09-23: The Calendula Challenge in 24 hours

The Calendula Challenge will soon begin. A 13 day (24 Sept - 7 Oct) Challenge is being offered on The Prime Sierpinski Problem (LLR) application. For more information, please see this forum post.

Come early and participate in the "All hands on deck" request for PPS (LLR). This is a GREAT warm-up ahead of the Challenge.

2010-09-21: The Calendula Challenge in 3 days

In 3 days, the Calendula Challenge will begin. Come watch the flowers bloom and hopefully find a 3 million digit Mega Prime! A 13 day (24 Sept - 7 Oct) Challenge is being offered on The Prime Sierpinski Problem (LLR) application. For more information, please see this forum post.

Also, come visit the forum and read about the "All hands on deck" request for PPS (LLR). This is a GREAT warm-up ahead of the Challenge.

2010-09-19: New badge level

A new badge level, Ruby, has been added, and badge level for Amethyst has been lowered.

The current badge levels are:
For LLR projects: 10 / 100 / 500 / 1000 / 2000 thousand credits; For Sieve/AP projects: 20 / 200 / 1000 / 2000 / 4000 thousand credits.

Here's an example of the new badge for your viewing pleasure:

2010-09-14: The Calendula Challenge

PrimeGrid's Challenge Series continues with the "Calendula Challenge". Come join us on this year's most grueling Challenge...of course, it will be the most rewarding Challenge as well for Challenge Points. A 13 day (24 Sept - 7 Oct) Challenge is being offered on The Prime Sierpinski Problem (LLR) application. A prime, if found, will be over 3 million digits long and rank as the 11th largest prime. For more information, please see this forum post.

2010-08-24: Planned maintenance tonight

Tonight we might have a downtime because of some maintenance in the datacenter. Fill your caches!

[update] After the maintenance the servers did not respond so we had to do a hard reboot. Hopefully everything is fine now.

2010-08-19: The Dog Days of Summer in 24 hours

When will the end come to this summer heat??? As soon as Sirius is separated from the sun!!! In 24 hours, come join us to help hasten Sirius' departure and thus, bring back cooler days. A 48 hour Challenge is being offered on the 321 Prime Search (Sieve). For more information, please see this forum thread.

2010-08-18: The Dog Days of Summer in 2 days

The time draws near to the chase. Sirius must be driven away from the Sun so that we can rid ourselves of this long hot sweltering summer (Northern Hemisphere). In 2 days, the Dog Days of Summer Challenge will begin. The 48 hour Challenge is being offered on PrimeGrid's 321 Prime Search (Sieve) application. Please come join us as we quicken the return of cooler days. :) For more information, please see this forum thread.

2010-08-16: PrimeGrid Donation Drive 2010 Fall

PrimeGrid is a project that is not financed by universities or commercial entities. In fact, all of our funding comes from the community, most of it through the donations page and a small amount through Google ads on the site. In the previous months donations were enough to cover all expenses running the website, however, the last few months have been particularly bad and just paying for server collocation has cut deep into our emergency funds.

It is never easy to be asking for money, but it has come to the point where we have to. We currently have money to keep the servers running for two more months. After that, we either shut down or throttle down significantly, which would be a shame having established PrimeGrid as a significant power in the prime number community, and having received uncountable hours of support from the members.

Therefore, we are launching PrimeGrid Donation Drive 2010 Fall. We have set the target to รขโ€šยฌ4000, which would allow us continue the service for a whole year and would also restore our emergency funds.

No matter how small the donation, it still helps! However, we have to keep the minimum amount at รขโ€šยฌ2 because of PayPal fees (if you prefer to donate through bank transfer, we have bank accounts in the Netherlands, Germany and Lithuania - please write a private message to me and the details will be sent to you).

To help keep the project running, please visit donations page, select the donation drive item and make a donation that you feel is suitable. Thank you in advance!

Update 2010-08-17 07:30 Big thanks to everyone who has donated already, we have almost reached 15% of the target amount. In addition, we now have a German bank account for direct transfer. If you want to make a direct deposit, please let me know by a private message.

2010-08-10: The Dog Days of Summer Challenge

The Dog Days are approaching! In just 10 days, PrimeGrid's Challenge series continues with the Dog Days of Summer Challenge. Please come join us in ushering an end to the hot sweltering days of summer. A 2 day (20-22 August) Challenge is being offered on PrimeGrid's 321 Prime Search (Sieve) application. Builds are available for Linux, Mac and Windows. For more information, please see this forum thread.

2010-07-24: The Full Moon Challenge - 24 hrs to go

There is coming soon a gathering of Warewolves and Prime Hunters. Be sure not to mix the two groups up or you might find yourself surrounded by blood thirsty animals!! ;) However, some might say that the two groups are NOT mutually exclusive. :D Come join us this Full Moon for a sporting "hunt" of Top 5000 primes in the Proth Prime Search (LLR) project. Application builds are available for Mac, Linux, and Windows. For more information, please see this forum thread.

2010-07-21: The Full Moon Challenge

Come howl at the moon with us and "hunt" for Top 5000 primes. It's a GREAT opportunity for you to find one for yourself! Who knows, there may even be the rare Fermat number divisor. :) We hope to establish a single day record for finding Top 5000 primes!

A 24 hour Challenge (25 July) is being offered on PrimeGrid's Proth Prime Search (LLR) application. Builds are available for Mac, Linux, and Windows. For more information, please see this forum thread.

2010-07-01: PSP finds another Mega Prime

The Prime Sierpinski Project has discovered their third Mega Prime: 90527*2^9162167+1. It is 2,758,093 digits long and will rank as the 12th largest known prime. The project has now found 18 primes total. There are 11 primes left to solve the Prime Sierpinski Problem. For more information, please see this forum post.

2010-06-16: 9 hours til the Birthday/Summer Solstice Challenge

9 hours remain til the "Birthday/Summer Solstice Challenge". Come join us in a 5 day celebration of PrimeGrid's 5th birthday. The 16-21 June Challenge on the The Riesel Problem (Sieve) application will culminate with a finale on the Summer Solstice. For more information, please see this forum post.

2010-06-15: 100M Cobblestones

A belated congratulations to shanky123 of Norway, for becoming the first single user account to reach 100M cobblestones (10 June) at PrimeGrid. An outstanding and amazing accomplishment after being here for just over 9 months.

Additionally, BOINCstats has just become only the 5th team to surpass 100M cobblestones. Congratulations all around.

2010-06-13: Unexpected outage

We had an unexpected network and power outage at the datacenter where PrimeGrid and BOINCstats are hosted, resulting in downtime of about an hour. The service has been restored now.

Update 19:01 UTC. We will remain down until database verification completes and we are sure we have no problems.
Update 19:20 UTC. Database has been checked and we're now sending and receiving work.

2010-06-09: 7 days til the Birthday/Summer Solstice Challenge

Just under a week remains til the "Birthday/Summer Solstice Challenge". Come join us as we celebrate PrimeGrid's 5th birthday. A 5 day (16-21 June) Challenge is being offered on The Riesel Problem (Sieve) application. Note the special start time of 11:28 UTC so that the Challenge can end exactly on the Summer Solstice. For more information, please see this forum post.

2010-06-04: PrimeGrid's Birthday/Summer Solstice Challenge

PrimeGrid's Challenge Series continues with the "Birthday/Summer Solstice Challenge". Come join us as we celebrate PrimeGrid's 5th birthday. A 5 day Challenge is being offered on The Riesel Problem (Sieve) application. The celebration will culminate on 21 June, the Summer Solstice. For more information, please see this forum post.

2010-05-11: Server software upgrade

Server software has been upgraded to the latest version. It brings serveral improvements, mostly visible one probably is news forum where you can comment directly on news items.

However, as with every upgrade, there might be something that breaks, so in case you find anything not working or working not like it did previously, and you think that it's a bug, please report it in the comments for this newspost. Thanks!

2010-05-02: 200M Cobblestones

Congratulations to SETI.Germany, the first team to reach 100M cobblestones at PrimeGrid...doubling their 100M cobblestone achievement in just over 9 months!!! :)

2010-04-26: Mega Prime for 321 Prime Search

Finally!!! A significant find during a Challenge. :) On 24 Apr 2010 11:40:07 UTC, PrimeGrid's 321 Prime Search found another Mega Prime:
3*2^6090515-1
The prime is 1,833,429 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 17th overall. This is the second mega prime for the 3*2^n-1 form, and it is the third largest found mega-digit prime using LLR. The discovery was made by David Mumper (Mumps) of the United States using an AMD Quad-Core Opteron 2378 with 8 GB RAM running Linux. This computer took just over 15 hours 24 minutes to complete the primality test. David is a member of the SETI.USA team. Official announcement and decimal representation of the prime.

2010-04-22: Earth Day Challenge

Turn the turbines into the wind and the solar panels towards the sun because in less than 13 hours, the Earth Day Challenge will begin. :) Come join us for an Earth Day (22 April) + 7 day Challenge on the 321 Prime Search (LLR) application. Even if you are not able to access "green" energy, check out the Earth Day discussion thread on other ways to offset your Challenge power consumption. For more information, please see this forum post.

2010-04-16: Earth Day Challenge

Earth Day is less than a week away. Hopefully the wind turbines are spinning and the solar panels are soaking up the sunlight. Come join us for an Earth Day (22 April) + 7 day Challenge on the 321 Prime Search (LLR) application. Even if you are not able to access "green" energy, check out the Earth Day discussion thread on other ways to offset your Challenge power consumption. For more information, please see this forum post.

2010-04-12: First ever AP26 Found!

The search is over. A World Record AP26 (Arithmetic Progression of 26 primes) has been found. The finder is Benoรฃt Perichon [AF>HFR>RR] Jim PROFIT) of France. He is a member of the L'Alliance Francophone team. The AP26 progression is written as 43142746595714191+23681770*23#*n for n=0..25. It was found by a PS3 running Linux. For more details on this find, please see this forum post. Congratulations to everyone who participated in the AP26 Search. It has been a very challenging and rewarding project. Also, a special thanks to all the programmers who ported AP26 making it the most accessible project at PrimeGrid. Note: there will be no more work once the queue is empty, so we would like to ask people not running for the badges to stop running AP26 subproject and give a chance for others to reach their final levels.

2010-04-08: Earth Day Challenge

Earth Day is approaching so grab a couple of wind turbines and some solar panels and come join us for an Earth Day Challenge. Starting 22 April 2010, Earth Day, PrimeGrid will continue its Challenge series with an Earth Day + 7 day Challenge on the 321 Prime Search (LLR) application. Even if you are not able to access "green" energy, check out the Earth Day discussion thread on other ways to offset your Challenge power consumption. That way you can "have your cake, and eat it too!" :D For more information, please see this forum post.

2010-04-02: PRPNet's Fool's Day Mini Challenge

PrimeGrid is stress testing the PRPNet software today in a PRPNet Fool's Day Mini Challenge. Why 2 April and not 1 April...because 2 is the first prime number. :) The initial stress test will last for 24 hours and start 2 April 2010 18:00 UTC. If all goes well, there will be an extended stress test that will last until 9 April 2010 18:00 UTC. If you have the time and energy, please stop by if even for just a little while. For more details, please see this forum post.

2010-04-02: Record AP25 Found

A new record AP25 (Arithmetic Progression of 25 primes) has been found. It is the largest known AP25 and the 15th discovered. It has an ending term of 183651856404750473 surpassing the previous record of 178450656331295477. The finder is Chris Wingate (skinny9699) of the United States. He is a member of the Ubuntu Linux team. The AP25 progression is written as 18626565939034793+30821486*23#*n for n=0..24. It was found in the AP26 Search by an NVIDIA GeForce GTX 285 on an AMD Phenom 9750 running Linux. For more details on this find and the AP26 search, please see this forum post.

2010-03-17: The Ides of March Challenge

"Et tu, Brute?" Yes, even Brutus stopped by and took down a few k/n pairs. He and the rest of the "senators" did the dirty work of rounding up over 400 prime wannabe's and placing them forever in the realm of composites. While they won't make the same notoriety as Caesar did, they will still rest in peace. The results are final. Just over 1.01P was sieved in the 24 hours of the Challenge...an astounding amount of work done. Congratulations to SETI.USA as the top team and Shanky as the top individual. Thank you to everyone who participated!!! For more stats and information, please see this forum post.

2010-03-14: The Ides of March Challenge

The k/n pairs in the sieve file have been warned against a great peril on the Ides of March. Yet they arrogantly hang around hoping to be proven prime. Well, in less than 24 hours, that hope will be replaced with sheer fright. Please come join us as an honorary "senator" and help bring some k/n pairs to their demise. A 24 hour (15-16 Mar) Challenge is being offered on PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application. For more information, please see this forum post.

2010-03-14: Record AP25 Found

A new record AP25 (Arithmetic Progression of 25 primes) has been found. It is the largest known AP25 and the 14th discovered. It has an ending term of 178450656331295477 surpassing the previous record of 144822829106549969. The finder is Dave Sunderland (DaveSun) of the United States. The AP25 progression is written as 25300381597038677+28603610*23#*n for n=0..24. It was found in the AP26 Search by an Intel Pentium 4 3.20GHz running 32 bit Windows XP Professional. For more details on this find and the AP26 search, please see this forum post.

2010-03-14: The Ides of March Challenge

The k/n pairs in the sieve file have been warned against a great peril on the Ides of March. Yet they arrogantly hang around hoping to be proven prime. Well, in less than 24 hours, that hope will be replaced with sheer fright. Please come join us as an honorary "senator" and help bring some k/n pairs to their demise.A 24 hour (15-16 Mar) Challenge is being offered on PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application. For more information, please see this forum post.

2010-03-09: The Ides of March Challenge

Less than one week till it's the end for some prime wannabe's. A 24 hour (15-16 March) Challenge is being offered on PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application. Come join us as we quicken the demise for some unlucky k/n pairs. Application builds are available for MacIntel, Linux, and Windows - with a 64 bit advantage. For more information, please see this forum post.

2010-03-01: Tour de Primes 2010 has ended!!!

A very productive month for the Tour de Primes. 309 "Top 5000" primes were discovered, easily surpassing last year's mark of 212. lennart SM5YMT of Sweden and the PrimeSearchTeam once again topped the leader boards winning his second yellow jersey in a row. He also picked up the green jersey for the first time. [SG]marodeur6 of Germany and team SETI.Germany takes home the checkered jersey. For more details about the tour and complete standings, please see this forum post.

2010-03-01: BEWARE the Ides of March!!!

PrimeGrid's Challenge series continues with the Ides of March Challenge. Once again we observe Caesar's demise by finding factors that will bring some k/n pairs to their demise. A 24 hour (15-16 March) Challenge is being offered on PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application. For more information, please see this forum post.

2010-02-25: New AP25 Found

A new AP25 (Arithmetic Progression of 25 primes) has been found. It is the 13th discovered. The finder is Keith Pattenden ([url=http://www.primegrid.com/show_user.php?userid= 18217]KWSN - Sir Brian - err sorry - wrong film![/url]) of the United Kingdom. He is a member of the The Knights Who Say Ni! team. The AP25 progression is written as 42592855872841649+19093314*23#*n for n=0..24. It was found by an NVIDIA GeForce GTX 260 in an Intel Core2 Quad 6600 @ 2.40GHz running 32 bit Windows XP Professional. For more details on this find and the AP26 search, please see this forum post.

2010-02-24: New AP25 Found

A new AP25 (Arithmetic Progression of 25 primes) has been found. It is the 12th discovered. The finder is Bryan Little (mfl0p) of the United States. He is a member of the [H]ard|OC team. The AP25 progression is written as 58555890166091939+10416756*23#*n for n=0..24. It was found by an NVIDIA GeForce GTX 260 in an Intel Core2 Quad @ 2.40GHz running Linux. For more details on this find and the AP26 search, please see this forum post.

2010-02-23: The Year of the Tiger Challenge

The results are final. Cupid and the Tiger ravaged the primes - bringing in an unprecedented 110 "new" primes to the Prime Pages with over half of those making it into the Top 1000. Over 2M tasks (1M WU's) were completed resulting in over 23M cobblestones awarded...an astounding amount of work done for an LLR Challenge. Congratulations to SETI.USA as the top team and Mr. Hankey as the top individual. Thank you to everyone who participated!!! For more stats and information, please see this forum post.

2010-02-21: Planned maintenance

We will be doing software upgrades on the servers in the upcoming few hours that might make the website temporarily inaccessible. We will update this post when the updates are complete. Update 14:05 UTC: maintenance has been completed successfully. Update 15:07 UTC: turns out database is misbehaving, so we need to extend the outage. Update 17:00 UTC: it seems that everything is running fine.

2010-02-17: The Year of the Tiger Challenge

Less than 4 hours remain. The hunt has been very successful for Cupid and the Tiger. Just as PrimeGrid's validator is struggling to keep up with the Challenge, the Prime Pages' validator is struggling to keep up with the prime submissions. :D Over 75 "Top 5000" primes have been found so far!!! There's still time to join the hunt. For more information, please see this forum thread.

2010-02-15: The Year of the Tiger Challenge

24 hours into the Challenge and Cupid and the tiger have been very successful in their hunt for primes - already snagging over 35 "Top 5000" primes. 48 hours remain so it's not too late to jump in the fray and see if you too can capture a prime. For more information, please see this forum thread.

2010-02-13: The Year of the Tiger Challenge

Only 24 hours remain till the start of the 2010 Challenge Series and Valentine's Day in the West and the Year of the Tiger in the East. Cupid is flying overhead while the tiger circles below. Please come join us in an East & West fearless attack on Proth Primes. A 3 day (14-17 Feb) Challenge is being offered on PrimeGrid's Proth Prime Search (LLR). Application builds are available for Mac, Linux, and Windows. For more information, please see this forum thread.

2010-02-07: The Year of the Tiger Challenge

One week till the start of the 2010 Challenge Series with the Year of the Tiger. A 3 day (14-17 Feb) Challenge is being offered on PrimeGrid's Proth Prime Search (LLR). Come join us as we stalk the primes. Application builds are available for Mac, Linux, and Windows. For more information, please see this forum thread.

2010-02-05: 49 digit factor to F14!!!

GIMPS has found another Fermat factor, a 49 digit factor to F14!!! What makes this unique and exciting is that it is the first factor for F14. It was found by Tapio Rajala of Finland. For more information on this discovery, see this mersenne forum thread. For more information about Fermat factors in general, please see Wilfrid Keller's Prime factors of Fermat numbers site.

2010-02-04: 49 digit factor to F14!!!

GIMPS has found another Fermat factor, a 49 digit factor to F14!!! What makes this unique and exciting is that it is the first factor for F14. It was found by Tapio Rajala of Finland. For more information on this discovery, see this mersenne forum thread. For more information about the factoring status of Fermat numbers, please see Wilfrid Keller's Prime factors of Fermat numbers site.

2010-02-04: 54 digit factor to F14!!!

GIMPS has found another Fermat factor, a 54 digit factor to F14!!! What makes this unique and exciting is that it is the first factor for F14. It was found by Tapio Rajala of Finland. For more information on this discovery, see this mersenne forum thread. For more information about the factoring status of Fermat numbers, please see Wilfrid Keller's Prime factors of Fermat numbers site.

2010-02-03: The Year of the Tiger Challenge

We are kicking off the 2010 Challenge Series with the Year of the Tiger Challenge which just so happens to coincide with Valentine's Day in the West. The Tiger is the third sign in the Chinese Zodiac cycle, and it is a sign of fearlessness. It is considered incredibly brave, evidenced by its willingness to engage in battle. So whether it's your love of Tigers or love of primes, please come join us in an East & West fearless attack on Proth Primes. A 3 day (14-17 Feb) Challenge is being offered on PrimeGrid's Proth Prime Search (LLR). Builds are available for Mac, Linux, and Windows. For more information, please see this forum thread.

2010-02-02: New AP25 Found

A new AP25 (Arithmetic Progression of 25 primes) has been found. It is the 11th discovered. The finder is Jan Stenzel (Jan Stenzel) of Poland. He is a member of the BOINC@Poland team. The AP25 progression is written as 49644063847333931+7851809 *23#*n for n=0..24. It was found by an Intel Core i7 860 @ 2.80GHz running 64 bit Windows 7. For more details on this find and the AP26 search, please see this forum post.

2010-02-01: Tour de Primes 2010

The Tour de Primes begins. Come join us in laid-back competition in tribute to the number 2...the first prime and the only even prime. The prizes are simple colored jerseys . Yellow for the most primes, Green for the highest prime score, and Checkered for the most primes on 17 Feb. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2010.

2010-01-31: Seventeen or Bust

On the eve of the Tour de Primes 2010, we are happy to announce that PrimeGrid is partnering with Seventeen or Bust to help solve the Sierpinski problem! This finally brings PrimeGrid full circle with SoB/PSP primality testing as well as combined sieving. Special thanks to Louis Helm of Seventeen or Bust for helping to make this collaboration possible! For more details on the new search, please see this forum thread.

2010-01-30: Tour de Primes 2010

February is a couple of days away which means it's time for the Tour de Primes. 2 is the first prime number...and the only even one. Therefore, we have declared February, the 2nd month, as prime month. We're offering a small competition in tribute to this unique prime number. There are no points to be gained or awards to be won...just a simple colored jersey (Yellow, Green, and Checkered) at the end of the month. No pressure or stress other than what you put on yourself. :) For more information, please see Tour de Primes 2010.

2010-01-15: New AP25 Found

A new AP25 (Arithmetic Progression of 25 primes) has been found. It is only the 10th discovered. The finder is Gerrit Slomma (roadrunner_gs) of Germany. He is a member of the Special: Off-Topic team. The AP25 progression is written as 46428033558097831+12893265*23#*n for n=0..24. It was found by an Intel Core2 6400 @ 2.13GHz running Linux. For more details on this find and the AP26 search, please see this [url=http://www.primegrid.com/forum_thread.php?id=1246&nowrap=true# 20398]forum post[/url].

2010-01-05: New AP25 Found

A new AP25 (Arithmetic Progression of 25 primes) has been found. It is only the 9th discovered. The finder is Dan Swearingen (endearingswan) of the United States. The AP25 progression is written as 24715375237181843+19071018*23#*n for n=0..24. It was found by an Intel Pentium 4 @ 3.00GHz running 32 bit Windows XP Professional. For more details on this find and the AP26 search, please see this forum post.

2009-12-26: Megabit Prime for 27121 Search

On 23 Dec 2009, PrimeGrid's PRPNet found a megabit prime: 27*2 2218064+1 The prime is 667,706 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 56th overall. The discovery was made by Honza Cholt (Honza) of the Czech Republic using a dual Intel Xeon @ 3.06GHz with 4GB RAM. This computer took 2 hours 38 minutes and 59 seconds to complete the primality test. Honza is a member of the team BOINC.SK For more details about this search, please see this forum thread.

2009-12-24: 2009 Challenge Series

PrimeGrid's 2009 Challenge Series has concluded. Congratulations to SETI.Germany (repeat Champion) as the top team and j2satx as the top individual. They are the overall winners to PrimeGrid's 2009 Challenge Series. For a list of other top finishers, please see this forum thread. As always, thank you for your help and support. None of this is possible without YOU! :) Have a safe and happy Holiday season. See you next year for PrimeGrid's 2010 Challenge Series!

2009-12-21: The Winter Solstice Challenge

The Winter Solstice is here!!! And the results are final. But the night is far from dark. The solstice fires are brighter than ever as the final Challenge of 2009 also happens to be the most active Challenge to date. Over 970K WU's were completed resulting in over 34.4M cobblestones awarded...an astounding amount of work done. Although no AP26 was found, six new AP24's were found along with countless smaller ones. Congratulations to SETI.USA as the top team and Mr. Hankey as the top individual. For more stats and information, please see this forum post This concludes PrimeGrid's 2009 Challenge Series. Overall final results will be posted soon. Many thanks goes out to everyone who participated!!! We wish you a Happy Holidays and see you next year!

2009-12-21: The Winter Solstice Challenge

The Winter Solstice is in 3 hours...and so too is the conclusion of the Challenge. Now is the time to start preparing for the finale. Please remember to upload early and often. The server is going to get hit hard as the Challenge draws to an end. We will start to lower "max cache" to help with this. There continues to be a lot of close races so don't miss out on your completed WU's. Best of Luck in these last 3 hours.

2009-12-20: The Winter Solstice Challenge

Over half way through and the solstice fires are exceptionally bright. So far four new AP24's have been found. Also, there are several very close races in the individual category. The Winter Solstice is almost upon us. It is not too late to come join the Winter Festival and warm yourself by the fires. For more information on how to join, please see this forum thread.

2009-12-18: The Winter Solstice Challenge

Only 13 hours remain till the Winter Solstice Challenge. The pre-fires have a nice red glow, and we're expecting them to turn a deep blue once the Challenge begins. Who knows...by the end of the Challenge they may even become white hot. :) Please come join us in a Winter Festival that is sure warm you up. The top spots for the 2009 Challenge Series are up for grabs. A 3 day (72 hour) Challenge is being offered on PrimeGrid's AP26 Project. Builds are available for Mac, Linux, Windows, Solaris, Cell/BE Linux (Playstation 3), and for the first time, GPU-CUDA23 app. For more information on how to join, please see this forum thread.

2009-12-17: Record AP25 & AP24 Found

A new record AP25 (Arithmetic Progression of 25 primes) has been found. It is the largest known AP25 and only the 6th discovered. It has an ending term of 139751114244588403 surpassing the previous record of 52115444782777781. It also includes the largest known AP24 with an ending term of 139751114244588403 surpassing the previous record of 108936498476106241. The finder is Rune Nordbรธe Skillingstad (runesk) of Norway. He is a member of Team Norway. The AP25 progression is written as 12353443596260323+23793841*23#*n for n=0..24. The AP24 progression is written as 12353443596260323+23793841*23#*n for n=1..24. It was found in the AP26 Search by an NVIDIA GeForce GTX 285 on an Intel i7 CPU 940 @ 2.93GHz running 32 bit Windows...the first significant AP found by a GPU!!! For more details on this find and the AP26 search, please see this forum post.

2009-12-16: The Winter Solstice Challenge

Just under 48 hours remain till the Winter Solstice Challenge. Please come join us in a Winter Festival that is sure to warm you up. If the run-up to the start is any indication, the solstice fires will be burning bright. As the team and individual rankings are so close, this Challenge will determine who takes home the 2009 Challenge Series top spot. A 3 day (72 hour) Challenge is being offered on PrimeGrid's AP26 Project. Builds are available for Mac, Linux, Windows, Solaris, Cell/BE Linux (Playstation 3), and for the first time, GPU-CUDA23 app. For more information on how to join, please see this forum thread.

2009-12-13: Megabit Prime for 12121 Search

On 4 Dec 2009, PrimeGrid, in collaboration with 12121 Search, found a megabit prime: 27*2 1902689-1 The prime is 572,768 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 76th overall. The discovery was made by Peter Kaiser (Puzzle-Peter) of Germany using a dual Intel Xeon X5472 @3.0GHz with 16GB RAM. This computer took 59 minutes and 17 seconds to complete the primality test. Peter is a member of the team SETI.Germany. For more details about this search, please see this forum thread.

2009-12-10: AP26 CUDA Application Released

Initial testing has gone well. Therefore, the AP26 CUDA application has been publicly released for 32 bit Windows (will run on 64 bit) and for 64 bit Linux. For more "important" information about the release, please see this forum thread.

2009-12-10: Possible issues because of GPU apps.

We are working on GPU apps now so you can expect some glitches in work distribution.

2009-12-09: World Record Generalized Woodall Prime

Those with triskaidekaphobia can rest at ease tonight!!! A generalized Woodall prime for base 13 has been discovered!!! The prime was found in PrimeGrid's PRPNet and is the largest known generalized Woodall prime: 563528*13563528-1 The prime is 627,745 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 1st for generalized Woodall primes and 65th overall. It is the largest non-base 2/non-generalized Fermat prime ever found. The discovery was made by Lennart Vogel (lennart SM5YMT) of Sweden using an Intel Q6600 @ 2.4 GHz with 4 GB RAM. This computer took about 3 hours and 54 minutes to complete the probable prime test. It took just over 30 hours to prove primality. For more details, please see the official announcement.

2009-12-04: The Winter Solstice Challenge

PrimeGrid's Challenge series continues with the Winter Solstice Challenge. Please come join us in observing Nature's ending/beginning of a cycle...a Winter Festival to determine who will take home the 2009 Challenge Series top ranking. There is a tie in the team category and a very close race among the top 3 in the individual category. :) A 3 day (18-21 Dec) Challenge is being offered on PrimeGrid's AP26 Project. Builds are available for Mac, Linux, Windows, Solaris, Cell/BE Linux (Playstation 3), and for the first time, possibly a GPU app. For more information, please see this forum thread.

2009-11-29: 13 Gold Badges

Congratulations to Bruno Courty (bcoz) of France, PrimeGrid's first participant to achieve a GOLD badge in all 13 projects. This is quite a remarkable feat. A complete set of badges is a major milestone, but 13 GOLD badges is a phenomenal achievement. Bruno has been a participant at PrimeGrid since 27 Feb 2007 and is a member of the team L'Alliance Francophone. He is one of the lucky ones who received a TPS gold badge before the twin prime was found. Thank you to everyone participating. We hope to see many more achieve this milestone!

2009-11-25: Record AP25 Found

A new record AP25 (Arithmetic Progression of 25 primes) has been found. It is the largest known AP25 and only the 5th discovered. It has an ending term of 52115444782777781 surpassing the old record of 38271649410634609. The finder is Ian Dickinson (Vato) of the United Kingdom. He is a member of Team-Goobee.org. The progression is written as 46176957093163301+1109121*23#*n for n=0..24. It was found in the AP26 Search by an Intel Pentium III @ 1266MHz running 32 bit Linux!!! For more details on this find and the AP26 search, please see this forum post.

2009-11-15: The Giving Thanks Challenge

The results are final. Over 191K tasks were returned resulting in almost 575T completed for the PSP/SoB sieve. Congratulations to SETI.Germany as the top team and [XTBA>XTC] FRED as the top individual. In the overall Challenge Series standings, there is now a tie for the top spot between SETI.GERMANY and BOINCstats. There is also a tie for second in the individual rankings with [SG]marodeur6 and [XTBA>XTC] FRED. This sets the stage for an exciting finale in the Winter Solstice Challenge. Thank you to everyone who participated!!! For more stats and information, please see this forum post.

2009-11-13: Record AP24 Found

A new record AP24 (Arithmetic Progression of 24 primes) has been found. It is the largest known AP24. It has an ending term of 104710589416588949 surpassing the previous record of 98090802848850701. The finder is Roald Solbjรธrg (Roald) of Norway. He is a member of Team Norway. The progression is written as 4891686128805269+19453568*23#*n for n=0..23. It was found by a PS3 in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-11-12: The Giving Thanks Challenge

Less than 24 hours remain till the Giving Thanks Challenge. Come join us in a 1 day (24 hour) Challenge on PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application. Please consider running a few PSP/SoB (Sieve) WU's before the Challenge begins so your client will already have the sieve file. This way, during the Challenge, bandwidth can be used to deliver WU's instead of the sieve file. :) Thank you! For more information, please see this forum thread.

2009-11-11: The Giving Thanks Challenge

PrimeGrid's Challenge series continues with the Giving Thanks Challenge. Please come join us in a celebration of PrimeGrid's users. In this season of giving thanks, we wish to thank you, the user, for another AMAZING year of crunching. A 24 hour (13-14 November) Challenge is being offered on PrimeGrid's Prime Sierpinski Problem/Seventeen or Bust (sieve) application. Builds are available for Mac, Linux and Windows. For more information, please see this forum thread.

2009-11-10: Generalized Fermat Prime Search

The Generalized Fermat Prime Search has been launched in PrimeGrid's PRPNet. This is a search for primes of the form b^2^n+1. They are named after Pierre de Fermat, considered to be one of the greatest French mathematicians of the seventeenth century. For more information, please visit this forum post.

2009-11-09: Record AP24 Found

A new record AP24 (Arithmetic Progression of 24 primes) has been found. It is the largest known AP24. It has an ending term of 98090802848850701 surpassing the old record of 93004136079654607. The finder is Marcus Rosario (Ritzgit) of the United States. He is a member of the Gay USA team. The progression is written as 4687877159107031+18203167*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-11-05: Record AP24 Found

A new record AP24 (Arithmetic Progression of 24 primes) has been found. It is the largest known AP24. It has an ending term of 93004136079654607 surpassing the old record of 90769015637524109. The finder is Chris Wingate (skinny9699) of the United States. He is a member of the Ubuntu Linux team. The progression is written as 1948053460212667+17745794*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-11-01: Record AP24 Found

A victory for the legacy systems!!! A new record AP24 (Arithmetic Progression of 24 primes) has been found. It is the largest known AP24. It has an ending term of 90769015637524109 surpassing the old record of 84418532426419063. The finder is Ian Dickinson (Vato) of the United Kingdom. He is a member of Team-Goobee.org. It was found by an Intel Pentium III @ 1266MHz running 32 bit Linux!!! The progression is written as 3634080452156039+16981607*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-10-10: The Harvest Festival Challenge

The results are final. Over 1,490,000 tasks were completed by 200 teams and 1361 individuals resulting in over 100 new "Top 5000" primes. Congratulations to SETI.Germany as the top team and [SG]marodeur6 as the top individual. Many thanks goes out to everyone who participated!!! For more stats and information, please see this forum post.

2009-10-10: Record AP24's Found

Several new AP24's (Arithmetic Progression of 24 primes) have been found...two of which are records. They were found in the AP26 Search. For more details on these finds and the AP26 search, please see this forum thread.

2009-09-28: The Harvest Festival Challenge

PrimeGrid's Challenge series continues with the Harvest Festival Challenge. Please come join us in a Fall harvest of primes. A 48 hour (02-04 October) Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. Builds are available for Linux, MacIntel and Windows. For more information, please see this forum thread.

2009-09-28: Unexpected outage

Today we experienced an unexpected outage lasting several hours. It was caused by database crash which has since been repaired. The server might be a little slow while it deals with work backlog, but all requests should go through eventually. We are very sorry for the inconvenience.

2009-09-19: Record AP24 Found

A new record AP24 (Arithmetic Progression of 24 primes) has been found. It is the largest known AP24. It has an ending term of 82761689028005821 surpassing the old record of 81531202836675089. The finder is Kevin Erickson (Kevin Erickson) of the United States. He is a member of the BOINCstats team. The progression is written as 10307159737232191+14120563*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-09-08: Record AP25 Found

PrimeGrid has found a record AP25 (Arithmetic Progression of 25 primes). This is PrimeGrid?s third AP25 and only the fourth known. It has an ending term of 38271649410634609 surpassing the old record of 37814740008933889. The finder is Keith Dale ([url=http://www.primegrid.com/show_user.php?userid= 42470]GreenFish[/url]) of the United States. He is a member of team SETI.USA. The progression is written as 18162964758258289+3755664*23#*n for n=0..24. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-09-03: Megadigit Probable Prime Found

Congratulations to Ben Maloney (paleseptember) who discovered the megadigit probable prime 2^4583176+2131. At 1,379,674 decimal digits, this is the first known probable prime with over a million digits. It should soon appear as the new probable prime record at the website of Henri and Renaud Lifchitz, PRP Records: Probable Primes Top 10000. Ben is participating in the project "Five or Bust" - The Dual Sierpinski Problem. This project is outside of PrimeGrid and can be located in the Mersenne forum. For additional information about this project, please see the Welcome to "Five or Bust!" thread. There are only 2 remaining sequences. To help with PRP testing, see this thread. To help with sieving, see this thread.

2009-09-02: Record AP25 Found

PrimeGrid has found a record AP25 (Arithmetic Progression of 25 primes). This is PrimeGrid?s second AP25 and only the third known. It has an ending term of 37814740008933889 surpassing the old record of 15523154536267043. The finder is Jochen Beck ([url=http://www.primegrid.com/show_user.php?userid= 25532]dh1saj[/url]) of Germany. He is a member of team SETI.Germany. The progression is written as 20919497549238289+3155495*23#*n for n=0..24. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-08-25: Record AP24 Found

Another record AP24 (Arithmetic Progression of 24 primes) found by a PS3. It is the largest known AP24. It has an ending term of 81531202836675089 surpassing the old record of 60739320360456407. The finder is Bryan Little (mfl0p) of the United States. He is a member of the [H]ard|OCP team. The progression is written as 13678065943093049+13223804*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-08-17: The Dog Days of Summer Challenge

The Dog Days are upon us! PrimeGrid's Challenge series continues with the Dog Days of Summer Challenge. Please come join us in ushering an end to the hot sweltering days of summer. A 5 day (18-23 August) Challenge is being offered on PrimeGrid's Woodall Prime Search (LLR)) application. Builds are available for Linux and Windows. For more information, please see this forum thread.

2009-08-16: Sophie Germain Prime Search

The long awaited debut of the Sophie Germain Prime Search has finally arrived. To participate, select Sophie Germain Prime Search (LLR) on your PrimeGrid preferences page. For more information, please see this forum post.

2009-08-14: A Request for Assistance

We are attempting to reach two BOINC users who have made significant prime discoveries at PrimeGrid. They are both active in other BOINC projects. Therefore, we would like to make a request to the entire BOINC community for help in finding these individuals. (KE7AAR) (UPDATE: Found) of the United States and team BOINC Synergy, shares credit for the World Record Twin Primes. (spinner@) of Japan and Team 2ch is the finder of the World Record Cullen Prime. If you have contact with either of these individuals, please have them check their BOINC emails or private messages in PrimeGrid's forum. Several attempts have already been made through these channels. Additionally, if you have any information that might help us in contacting these individuals, please contact us here: http://www.primegrid.com/contact.php (Update 2009-08-15 18:00 UTC) KE7AAR has been contacted, thanks to everyone for help!

2009-08-14: Cullen/Woodall Sieve

The Cullen/Woodall Sieve is active again. Both prime searches have reached n=7M in their primality testing. Therefore, combined sieving has begun on the next range of 10M PrimeGrid preferences[/url] page.

2009-08-09: 50M Cobblestones for SG Grid!!!

Congratulations to SG Grid, for becoming the first single user account to reach 50M cobblestones at PrimeGrid. An outstanding and amazing accomplishment after being here for less than 8 months.

2009-08-06: World Record Twin Primes returned

The search is finally over!!! The Twin Primes have been discovered!!! Verification was quickly completed and the appropriate users are being contacted. Credit will be shared between the finder, top producer in terms of M, top producer in terms of primes found, and top siever. The Twin Primes were actually returned on the SAME!!! day as the Cullen Prime but were overlooked in the excitement of the Cullen. Work generation has been terminated so please select another project if TPS was your only project. The project will remain active until all outstanding work has been returned and credited. Stay tuned for more details.

2009-08-05: World Record Cullen Mega Prime found

On 25 Jul 2009 1:11:48 UTC, PrimeGrid's Cullen Prime Search found another World Record Cullen Mega Prime: 6679881ยท26679881+1 The prime is 2,010,852 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th overall. It is the largest known Cullen prime and the largest found Mega Prime using LLR. This remarkable discovery comes less than 4 months after the last prime and is only the 16th known Cullen prime. Contact with PrimeGrid participant (spinner@) has not been returned. However, the participant is from Japan and is a member of Team 2ch. The prime was found using an Intel Xeon L5420 @ 2.50GHz with 6 GB RAM running Windows XP Professional. This computer took about 71 hours 58 minutes to complete the primality test. More details to come after contact is made.

2009-08-03: New AP24 Found

PrimeGrid has found a new AP24 (Arithmetic Progression of 24 primes)...the first by a PS3!!! The finder is Paolo Bassi ([FVG] bax) of Italy. He is a member of team BOINC.Italy. The progression is written as 25545151920212759+1140241*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-08-01: World Record Cullen Mega Prime returned

As unbelievable as it may sound, another Cullen Mega Prime has been discovered!!! It is only the 16th known Cullen prime. It is also a top 15 prime at over 2M digits and the largest found by LLR. Additionally, it is PrimeGrid's largest prime to date. The discoverer is from Japan and a member of Team 2ch. Verification is in progress. Stay tuned for more details.

2009-07-30: New AP24 Found

PrimeGrid has found a new AP24 (Arithmetic Progression of 24 primes). The finder is Jeffrey D Sessler (Tostada) of the United States. He is a member of team Ars Technica. The progression is written as 20187352211709911+1799216*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-24: New AP24's Found

While there were no AP24+ found during the Challenge, two AP24's actually were found in the hours leading up to the start. The finders are Andreas Mohr (andmore) of Germany and Tina Kent (Penguirl) of the United States. Andreas' progression is written as 19471368812966089+410682*23#*n for n=0..23 and Tina's progression is written as 20909681071069667+234797*23#*n for n=0..23. Both were found in the AP26 Search. For more details on these finds and the AP26 search, please see the following forum posts: Andreas' AP24 | Tina's AP24.

2009-07-24: 100M Cobblestones

Congratulations to SETI.Germany, the first team to reach 100M cobblestones at PrimeGrid...doubling their 50M cobblestone achievement in only 5 1/2 months!!! Is 150M in their sights by year's end? We'll have to wait and see. Again, congratulations! :)

2009-07-19: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the largest known AP24. It has an ending term of 62869009767207037 surpassing the old record of 60739320360456407. The finder is Jan-Cornelius Molnar (janm) of Germany. The progression is written as 10317962076055027+10241601*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-18: PlayStation3 application

We now have AP26 application for PlayStation 3. You may wish to check the forum thread in order to get it running at full speed. Thanks to mfl0p.

2009-07-18: Follow PrimeGrid on Twitter

For those of you using Twitter, you can now follow PrimeGrid and watch the progress of recent findings in the AP26 Search. PrimeGrid Twitter on Web: http://www.twitter.com/primegrid. Thanks to Lexs for implementing the updates script.

2009-07-18: New AP24 Found

PrimeGrid has found a new AP24 (Arithmetic Progression of 24 primes). The finder is Carsten Hartwig (SG Arsenic) of the United Kingdom. He is a member of the SETI.Germany team. The progression is written as 19516186145019209+313705*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-14: The New Moon Challenge

PrimeGrid's Challenge Series continues with the New Moon Challenge. Please come join us in ushering in July's New Moon along with a new project to the Challenge Series. A 24 hour (21 July ? 22 July) Challenge is being offered on PrimeGrid's AP26 (Arithmetic Progression of 26 primes) application. Builds are available for Linux, Mac, Windows, PS3, & Solaris. For more information, please see this forum thread. P.S. Also, the "most significant" Solar Eclipse this century is occuring on 22 July. :) See forum thread for more details.

2009-07-12: New AP24 Found

PrimeGrid has found a new AP24 (Arithmetic Progression of 24 primes). The finder is Bryan Little (mfl0p) of the United States. He is a member of the [H]ard|OCP team. The progression is written as 7979661543967237+9936237*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-10: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the AP24 with smallest known start. It has a starting term of 39421708111691 decreasing the old record of 167806194923077. The finder is Mark Codding (Narwhal) of the United States. He is a member of Team Picard. The progression is written as 39421708111691+9740894*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-06: New AP24 Found

PrimeGrid has found a new AP24 (Arithmetic Progression of 24 primes). The finder is Pawe? Feru? (mindc) of Poland. He is a member of the BOINC@Poland team. The progression is written as 5531900872160491+9383796*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-04: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the largest known AP24. It has an ending term of 60739320360456407 surpassing the old record of 60312982868878297. The finder is Carsten Hartwig (SG Arsenic) of the United Kingdom. He is a member of the SETI.Germany team. The progression is written as 13432401425380607+9219580*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-07-01: AP26 application available for Solaris

We have released a version of AP26 application for 64bit Solaris (on AMD x86_64 or Intel EM64T CPUs, platform name x86_64-pc-solaris). This is our first application for this platform, which also makes AP26 an application that runs on the most platforms. Thanks to Gerrit Slomma for building the app! Psst... the PS3 version is coming ;)

2009-06-30: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the largest known AP24. It has an ending term of 60312982868878297 surpassing the old record of 25490711550130537. The finder is (AFXTBA Pitheque) of France. He is a member of the L'Alliance Francophone team. The progression is written as 14992521666441877+8832442*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-06-20: New Top Host!

Congratulations to Worldwide Center of Mathematics, owner of the new top host at PrimeGrid. While this position has changed many times in the past, what makes this occasion unique is that this is the first time the top host is a Mac!!! EDIT: The above is in terms of RAC. In terms of total credit, UL1 holds a commanding lead of over 5M cobblestones with this host.

2009-06-15: The sieves have been Mac'd out!

321, PPS, and PSP sieves now have application support for Mac OS X 10.4 running on Intel and 10.5 running on 64bit Intel. PPS sieve also offers application support for Mac OS X 10.3 running on PPC.

2009-06-13: GIMPS does it again!!!

Congratulations to The Great Internet Mersenne Prime Search (GIMPS)! On April 12th, Odd Magnar Strindmo of Norway discovered the 47th known Mersenne prime, 2^42,643,801-1. It is the second largest known prime at 12,837,064 digits, only 141,125 digits smaller than the Mersenne prime found last August. The prime was independently verified June 12th. For more information, please visit the GIMPS site. Again, congratulations!!!

2009-06-11: PrimeGrid's Birthday/Summer Solstice Challenge

Just over 24 hours until the start of PrimeGrid's "Birthday/Summer Solstice Challenge". A 9 day Challenge is being offered on the Prime Sierpinski Problem (LLR) application. Long Challenge, long WU's, but the rewards are greater...250 Challenge points goes to the winner and should a prime be found, it will be a Mega Prime. For more information, please see this forum post.

2009-06-07: PrimeGrid's Birthday/Summer Solstice Challenge

PrimeGrid's Challenge Series continues with the "Birthday/Summer Solstice Challenge". A 9 day Challenge is being offered on the Prime Sierpinski Problem (LLR) application. We are celebrating PrimeGrid's 4th birthday on 12 June...culminating 21 June on the Summer Solstice. It seems fitting that the sun will shine the longest for the project with the longest WU. For more information, please see this forum post.

2009-05-29: Record APs Found

PrimeGrid has found two new records for AP22 and AP23 (Arithmetic Progression of 22 primes and 23 primes respectively). They are the smallest known starts for each of their classifications. The finders are Jacek Kotnowski (sosnahojna - team BOINC@Poland) of Poland for the AP22 record and Eric Markle (Nikodemus - team BOINCstats) of the United States for the AP23 record. They were found in the AP26 Search. For more details on these finds and the AP26 search, please see these forum posts - AP22, AP23.

2009-05-20: 1,000,000,000 cobblestones for PrimeGrid!!!

Today, PrimeGrid surpasses the 1 Billion mark in cobblestones. From meager beginnings on 12 June 2005 to now, a tremendous amount of work has been accomplished...6 mega primes, 3 Fermat Number divisors, and over 4000 titanic primes have been discovered. Congratulation goes out to the entire community for an incredible achievement. Thank you all for your support!

2009-05-17: Scheduled downtime

We are going to have a one to two hour downtime tomorrow, May 18, at about 12:00 GMT, because the servers have to be moved to a different rack as the datacenter is upgrading their infrastructure.

2009-05-15: New Points Leader

Congratulations to SG Grid, for becoming the new points leader at PrimeGrid. What makes this accomplishment more amazing is that it was done in less than 5 months. The two projects that have benefited the most from this achievement are the Twin Prime Search and the Prime Sierpinski Problem. Again, congratulations!

2009-05-13: PrimeGrid mentioned at TEDx talk

Watch a TEDx Warwick talk by Francois Grey about citizen cyberscience, which also mentions PrimeGrid (at about 8:20) or download the video (215MB). $f("player", "/flowplayer/flowplayer-3.1.0.swf", { clip: { url: '/download/TEDx/francois_grey.flv', autoPlay: false } });

2009-05-11: Mac OS X support!

We have released first PrimeGrid application for Mac OS X, Arithmetic Progression of 26 Primes Search (AP26). Mac OS X 10.3 running on PPC, 10.4 running on Intel and 64bit 10.5 running on Intel are supported. Thanks to Iain Bethune for compiling the apps.

2009-05-06: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the largest known AP24 as well as the AP24 with smallest known start. The finder is Andreas Kobara ([url=http://www.primegrid.com/show_user.php?userid= 20289]Lexs[/url]) of Germany. He is a member of the Gentoo Linux Users Everywhere team. The progression is written as 167806194923077+4935146*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-05-05: 50M Cobblestones

Congratulations to L'Alliance Francophone, for reaching the 50M cobblestones level at PrimeGrid. They are only the second team to accomplish this. It actually occurred during the Showers to Flowers Challenge so this is a bit belated. Again, congratulations!

2009-05-02: The Showers to Flowers Challenge

The results are final. Over 1169T was crunched in the 48 hours of the Challenge and over 389,000 tasks were completed by 260 teams and 2092 individuals. Congratulations to SETI.Germany as the top team and [AF>XTBA>XTC] FRED as the top individual. Many thanks goes out to everyone who participated!!! For more stats and information, please see this forum post.

2009-04-29: The Showers to Flowers Challenge

Let the "rains" begin!!! The Showers to Flowers Challenge has started. A 2 day (48 hour) Challenge is being offered on PrimeGrid's Prime Sierpinski Project (Sieve) application. For more information, please see this forum post.

2009-04-28: The Showers to Flowers Challenge

Only 24 hours remain until it starts "raining" factors. A 2 day (48 hour) Challenge is being offered on PrimeGrid's Prime Sierpinski Project (Sieve) application. Come join us for a shower of factors in hopes to make those hidden primes bloom. :) For more information, please see this forum post.

2009-04-21: World Record Cullen Mega Prime found

On 20 Apr 2009 0:52:45 UTC, PrimeGrid's Cullen Prime Search found a World Record Cullen Mega Prime: 6328548*26328548+1 The prime is PrimeGrid's largest prime to date. It is 1,905,090 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th overall. It is the largest Cullen prime found and the largest found Mega Prime using LLR. The discovery was made by Dennis R. Gesker (Gesker) of the United States using an Intel Xeon E5420 @ 2.50GHz with 8GB RAM running Windows Server 2008. This computer took 32 hours 28 minutes to complete the primality test. For more details, please see the official announcement. Decimal representation of the number is also available.

2009-04-20: World Record Cullen Mega Prime found

A PrimeGrid participant has discovered a World Record Cullen Mega Prime in the Cullen Prime Search. This is a very special and rare find. It is only the 15th Cullen prime known. It is also a top 15 prime and the largest found by LLR. Additionally, it is PrimeGrid's largest prime to date. Stay tuned for more details.

2009-04-09: Record AP25 Found

PrimeGrid has found a record AP25 (Arithmetic Progression of 25 primes). This is PrimeGrid's first AP25 and only the second known. It is the largest AP25 having an ending term of 15523154536267043 surpassing the old record of 8132758706802551. It is also the AP25 with smallest known start 2960886048458003, the previous record being 6171054912832631. The finder is BOINC@Poland's "Super Computer" (SKB@P). It is a farm of machines funded by BOINC@Poland members. The progression is written as 2960886048458003+2346233*23#*n for n=0..24. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-04-07: Record AP24 Found

PrimeGrid has found a record AP24 (Arithmetic Progression of 24 primes). It is the largest known AP24. It has an ending term of 19898154930924749 surpassing the old record of 19516877252820799. The finder is Pawel Stachowiak (stachu @ fiddex) of Poland. The progression is written as 7960592659339799+2326495*23#*n for n=0..23. It was found in the AP26 Search. For more details on this find and the AP26 search, please see this forum post.

2009-04-05: New AP24 Found

PrimeGrid has found a "New" Arithmetic Progression of 24 primes. The finder is Pawel Stachowiak (stachu @ fiddex) of Poland. The progression is written as 6274259724784693+2522655*23#*n for n=0..23. It was found in the AP26 Search. We expect to find many more and even a few AP25's along the way to the goal of an AP26. For more details on this find and the AP26 search, please see this forum post.

2009-04-05: 321 Prime Search finds a Mega Prime

On 3 Apr 2009 15:40:01 UTC, PrimeGrid's 321 Prime Search found another Mega Prime:3*25082306+1The prime is 1,529,928 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 15th overall. It is the 6th largest Proth prime found and the largest found Mega Prime using LLR. The discovery was made by Andy Brady (Andy Brady) of the United States using an Intel C2Q Q8200 @ 2.33GHz with 3GB RAM running Windows Vista. This computer took about 14 hours 7 minutes to complete the primality test. Andy is a member of the BOINCstats team. For more details, please see the official announcement. Decimal representation of the number is also available.

2009-04-04: 321 Prime Search finds a Mega Prime

A PrimeGrid participant has discovered a Mega Prime in the 321 Prime Search! We are currently GFN divisibility testing the prime as well as awaiting contact with the discoverer. It is a top 15 prime and the largest found by LLR. Stay tuned for more details.

2009-04-02: Fermat Number Divisor

Congratulations to Eric Embling (Eric E) of the United States, the discoverer of PrimeGrid's third Fermat Number divisor in the Proth Prime Search project: 659*2^617815+1 Divides F(617813). It is the 3rd found Fermat Number divisor of 2009 and 273rd overall. It is the 6th largest Fermat Number divisor in Chris Caldwell's The Largest Known Primes Database. Incidentally, it is a new record for "weighted" Fermat Number divisors. For more information, please see this forum post.

2009-03-28: New AP24 Found

PrimeGrid has found a "New" Arithmetic Progression of 24 primes. The finder is Krzysztof Koczubik (ksysju) of Poland. This is his second AP24 discovery. The progression is written as 6872932294461509+2042703*23#*n for n=0..23. It was found in the AP26 Search. We expect to find many more and even a few AP25's along the way to the goal of an AP26. For more details on this find and the AP26 search, please see this forum post.

2009-03-20: The Ides of March Challenge

The results are final. Over 550,000 tasks were completed by 148 teams and 901 individuals. Congratulations to BOINCstats as the top team and j2satx as the top individual. Many thanks goes out to everyone who participated!!! For more stats and information, please see this forum post.

2009-03-16: The Ides of March Challenge

The photo finish is in and it looks pretty clear that BOINCstats has taken the team standings and j2satx the individual standings (unofficial). What an incredible past 24 hours. Job well done everyone!!! Congratulations all around. As for the fate of the primes, you can still hear their sorrowful moans as they are hauled off to the Top 5000 list. More details to come.

2009-03-16: The Ides of March Challenge

Just under 1 & 1/2 hours remain. So far, a week's worth of primes have been found in less than 24 hours...with more still coming in. The team and individual competitions are still battling it out. A photo finish seems inevitable. Now is the time to start preparing for the conclusion. Update your clients early and update often. For more information, please see this forum post.

2009-03-16: The Ides of March Challenge

8 hours into the Challenge and the primes are beginning to fall. The start went exceptionally well with over 40K tasks going out in 30 minutes (11630 tasks in the first 5 minutes)!!! Well done everyone. The team and individual competitions are heating up with fierce battles going on for the top spots. Looks like it's shaping up for another "down to the wire" finish. For more information, please see this forum post.

2009-03-15: The Ides of March Challenge

T-minus 18 hours and counting. The sievers have the primes on the run. The Ides of March approaches and doom is in the air for these primes. Come join us for a 24 hour Challenge on the Proth Prime Search LLR project. For more information, please see this forum post.

2009-03-14: GCW13 Mini-Challenge

Friday the 13th has come and gone. Sadly, those elusive and unique GCW13 primes continue to elude us. Looks like Friday, November the 13th will get its chance at finding them. However, the results will be much different in just over a day and a half from now for The Ides of March Challenge. The question isn't will a prime be found...it's how many. In a tribute to the sievers, come join us for a 24 hour Challenge on the Proth Prime Search LLR project. For more information, please see this forum post.

2009-03-13: GCW13 Mini-Challenge

Friday, March the 13th is HERE!!! And still no sighting of the elusive Generalized Cullen or Woodall base 13 primes. Will today be the day, or will we have to wait until Friday, November the 13th? Come join for a final push today. For more information, please see this forum post.

2009-03-09: GCW13 Mini-Challenge

Friday, March the 13th, is approaching which means it's time for another "friendly" mini-challenge to find a Generalized Cullen or Woodall base 13 prime. As we discovered last time, this is no easy task. With St. Patrick's day around the corner, we'll need a little bit of that Irish Luck to come early. :) For more information, please see this forum post.

2009-03-07: Fermat Number Divisor

Congratulations to Senji Yamashita (s-yama) of Japan, the discoverer of PrimeGrid's second Fermat Number divisor in the Proth Prime Search project: 519*2^567235+1 Divides Fermat F(567233). It is only the 2nd found Fermat Number divisor of 2009 and 272nd overall. It is the 7th largest Fermat Number divisor in Chris Caldwell's The Largest Known Primes Database. Incidentally, it is a new record for "weighted" Fermat Number divisors. For more information, please see this forum post.

2009-03-06: New AP24 Found

PrimeGrid has found a "New" Arithmetic Progression of 24 primes. The finder is Stefan Smietanowski (Blast) of Sweden. The progression is written as 2725131905640097+1342336*23#*n for n=0..23. This was found in the AP26 Search. We expect to find many more and even a few AP25's along the way to the goal of an AP26. For more details on this find and the AP26 search, please see this forum post.

2009-03-05: The Ides of March Challenge

The countdown has started, T minus 10 days and counting. The sievers are hard at work behind the scenes factoring out all the prime wannabe's. Doomsday is approaching the remaining candidates as there is little room left to hide. Come 15 March, GLORY will go to the finders and the primes will face their nemesis, the Top 5000 List at the Prime Pages. Be sure to catch some of that GLORY in the 24 hour Ides of March Challenge. For more information, please see this forum post.

2009-03-03: Statically-linked LLR wrapper

The new LLR wrapper that was released two weeks ago has now been updated to be fully statically-linked. Testing has gone well in the Proth Prime Search project. Therefore, it has been released for all LLR projects which include 321 Prime Search, Cullen Prime Search, Prime Sierpinski Problem, Twin Prime Search, and the Woodall Prime Search. 32 bit Linux support continues on ALL LLR projects. Again, thanks to Geoff Reynolds who has made this build a reality!

2009-03-02: BEWARE the Ides of March!!!

If you are a prime, BEWARE the Ides of March!!! Right now, 100's of sievers are working behind the scenes to clear the path for the primality testers to find you. And on 15 March, your time is up!!! A 24 hour Challenge is being offered on PrimeGrid's Proth Prime Search (LLR) application. For more information, please see this forum post.

2009-03-01: Tour de Primes 2009 has ended!!!

There were no surprise sprints on this last day...just a nice champagne stroll around the Champs-Elysรฉes. Congratulations to the jersey winners: Yellow - Lennart; Green - s-yama; and Checkered - Lennart. For more details on the conclusion of the race, please see this forum post.

2009-02-26: New AP24 Found

PrimeGrid has found a "New" Arithmetic Progression of 24 primes. The finder is Krzysztof Koczubik of Poland. He is a member of BOINC@Poland. The progression is written as 13785500104035967+1004314*23#*n for n=0..23. This was found in the AP26 Search. We expect to find many more and even a few AP25's along the way to the goal of a record AP26. For more details on this find and the AP26 search, please see this forum post.

2009-02-19: 321 Sieve

The 321 Sieve has completed its manual effort and is now available in BOINC. Current depth is p=2P for 5M PrimeGrid preferences[/url]and select 321 Prime Search (Sieve). It's currently available for Linux64 and Windows32/64.

2009-02-18: Tour de Primes 2009

Over half way through the Tour de Primes and Lennart continues to hold a comfortable lead. A quick look at his primes and you can see that he's taking advantage of PPSE on PRPNet. With the mountain stage coming up on the 23rd, it's not too late to reel him back in. For more information, please see Tour de Primes 2009. For information about PRPNet, please see this forum post.

2009-02-17: New LLR Wrapper for Linux

A new LLR wrapper for Linux has been released. Along with this release, there is now Linux support for the Cullen Prime Search (LLR) and Prime Sierpinski Problem (LLR). A special thanks to Geoff Reynolds, who made this build a reality! For more information, please see this forum post.

2009-02-14: 12121 Prime Search

We are happy to announce that PrimeGrid is partnering with 12121 Search. Similar to 321 Search (k=3), 12121 Search is searching for single k primes of the form 121*2^n-1. They have been successfully searching since 2004 and are now in the Mega Prime area. For more details on the new search, please see this forum thread.

2009-02-10: Prime Month

The prime month competition is starting to heat up. Lennart has just recently broken away from the group and has a 3 prime lead. He has a mixture of BOINC and PRPNet primes. Is there anyone who can challenge him for the yellow jersey??? Just under 2/3's of the month remains so there's plenty of time for someone to rein him back into the peloton. For more information, please see this forum post.

2009-02-09: GCW13 Mini-Challenge

PrimeGrid user rogue has proposed a "friendly" mini-challenge to find a Generalized Cullen or Woodall base 13 prime on or before Friday, February 13th, 2009. A most ambitious endeavor! It will take the Luck of all the Irish PrimeGrid users for this prime to be found...especially on that date. However, to the finder goes all the spoils of fame (math fame) for these elusive gems! For more information, please see this forum thread.

2009-02-08: 50M Cobblestones

Congratulations to SETI.Germany, the first team to reach 50M cobblestones at PrimeGrid. Also, a special thanks to pschoefer, SETI.Germany's administrator at PrimeGrid, who does an excellent job managing PrimeGrid's information for such a large team. Now the race is on for 100M cobblestones...can it be reached by year's end??? and by which team??? :)

2009-01-31: The Year of the Ox Challenge

While the Challenge is over, the Year of the Ox is just beginning. Over 18,000 321 WU's were completed by 133 teams and 589 individuals. Congratulations to BOINCstats as the top team and WilliamWallace as the top individual. It was a GREAT start to the 2009 Challenge Series. Congratulations to everyone and thank you for participating!!! For more information, please see this forum post.

2009-01-27: The Year of the Ox Challenge

24 hours into the Year of the Ox Challenge and all is well. In just this short time, BOINCstats has taken a commanding lead while the individual competition is a bit closer. It's not too late to join the fireworks in a celebration of the Chinese New Year. For more information, please see this forum thread.

2009-01-25: The Year of the Ox Challenge

Just over 24 hours remain until the Year of the Ox Challenge. Come join the fireworks in a celebration of the Chinese New Year, the Year of the Ox. A 5 day (26th-31st Jan) Challenge is scheduled on PrimeGrid's 321 Prime Search LLR application. For more information, please see this forum thread.

2009-01-20: The Year of the Ox Challenge

PrimeGrid's 2009 Challenge Series starts off with a fire cracker bang! Please come join us in the Chinese New Year, the Year of the Ox, for a 5 day (120 hour - 26th-31st Jan) Challenge on PrimeGrid's 321 Prime Search (LLR) application. The Ox is the sign of prosperity through fortitude and hard work. It is unswervingly patient, tireless in its work, and capable of enduring any amount of hardship without complaint. Sounds a lot like prime searchers. :) For more information, please see this forum thread.

2009-01-16: Norton Antivirus alarms

We are seeing multiple workunit failures and trouble reports because of Symantec (Norton) antivirus marking our screensaver as a probable virus. While there is nothing we can do about it, you can exclude BOINC data directory from antivirus path, and contact Symantec telling them about the false positive. Please keep all discussions in this forum thread .

2009-01-01: First prime of 2009

Congratulations to zed, the discoverer of PrimeGrid's first prime for 2009 in the Proth Prime Search project: 15*2^483098+1. Unfortunately, it was just a double check. The first "new" prime of 2009 was found by Vato, again from the Proth Prime Search project: 835*2^483718+1.

2008-12-28: Fermat Divisor

Congratulations to Eric Ueda, the discoverer of PrimeGrid's first Fermat divisor in the Proth Prime Search project: 651*2^476632+1 Divides F(476624). It is only the 6th found Fermat divisor of 2008 and 270th overall. It is the 8th largest Fermat divisor in Chris Caldwell's The Largest Known Primes Database. For more information, please see this forum thread.

2008-12-27: AP26 Search

PrimeGrid has added a new prime search project, an Arithmetic Progression of 26 primes. An arithmetic progression of primes is a sequence of primes with a common difference between any two successive numbers in the sequence. For example 3, 7, 11 is an arithmetic progression of 3 primes with a common difference of 4. To participate, go to your PrimeGrid preferences page and select AP26 (currently only available for 64 bit Linux). For more information, please see this forum thread.

2008-12-26: Primorial Prime Search

PrimeGrid has added a new prime search project, the Primorial Prime Search. These primes are of the forms p#+1 and p#-1. It enters the Project Staging Area first as a manual sieving effort. Once sufficient depth has been reached, a primality testing effort will begin. For more information, please see this forum thread.

2008-12-24: 2008 Challenge Series

PrimeGrid's 2008 Challenge Series has concluded. Congratulations to SETI.Germany as the top team and lennart SM5YMT as the top individual. They are the winners to PrimeGrid's inaugural 2008 Challenge Series. For a list of other top finishers, please see this forum thread.

2008-12-24: The Winter Solstice Challenge

The results are in for the Winter Solstice Challenge. Thank you for your patience. The margin of victory is 0.055%. Congratulations to WilliamWallace as the top individual and BOINCstats as the top team. For more information, please see this forum thread. The crowning of the top overall finishers in PrimeGrid's 2008 Challenge Series is next.

2008-12-22: The Winter Solstice Challenge

The Solstice has come and gone. Twas a tough last 12 hours but we have survived the night and the sun has risen again! The Winter Solstice Challenge ended with a tremendous battle. It's still too close to call. Thank you to all who participated in what turned out to be PrimeGrid's top Challenge of the Year. It would not have been possible without your support. For more information, please see this forum thread. Stay tuned...final results will be coming soon.

2008-12-21: The Winter Solstice Challenge

'tis but 12 hours left till the Solstice. The fire is burning bright and there's plenty of logs to keep it alit til the sun's return at dawn. :) The team and individual races are as tight as ever. It looks like this will go down to the wire. :) Thank you everyone for making this the most exciting Challenge yet. For more information, please see this forum thread.

2008-12-20: The Winter Solstice Challenge

Only 24 hours remain until the Winter Solstice...the longest night/shortest day of the year. Although we are in the middle of winter in the northern hemisphere, the competition remains very hot...not to mention the heat coming off the cores. :) This is by far the most highly contested Challenge of the year. Most fitting for the finale in the 2008 Challenge series. For more information, please see this forum thread.

2008-12-18: The Winter Solstice Challenge

Over 24 hours into the 4 day (96 hour) Challenge and all is well. Everything is going quite smooth right now. Another record breaking amount of work is being completed. There are some close races in both the team and individual categories. It's not too late to join in and give your favorite team a boost. :) For more information, please see this forum thread.

2008-12-16: The Winter Solstice Challenge

Less than 24 hours remain till the Winter Solstice Challenge. Come join us in a 4 day (96 hour) Challenge on PrimeGrid's Prime Sierpinski Project (Sieve) application. Please consider running a few PSP (Sieve) WU's before the Challenge begins so your client will already have the sieve file. This way, during the Challenge, bandwidth can be used to deliver WU's instead of the sieve file. :) Thank you! For more information, please see this forum thread.

2008-12-10: The Winter Solstice Challenge

PrimeGrid's Challenge series for 2008 ends with the Winter Solstice Challenge. Please come join us in observing Nature's ending/beginning of a cycle. A 4 day (96 hour) Challenge is being offered on PrimeGrid's Prime Sierpinski Project (Sieve) application. For more information, please see this forum thread.

2008-12-07: The Prime Time Challenge (Exploded)

The database has finally started to recover from the Challenge...and we have finished licking our wounds. It was one heck of an initiation for the new server. The one positive outcome is that an incredible amount of work was completed (over 3.3M results in 48 hours). Again, the participation greatly exceeded our expectations. Congratulations to SETI.Germany as the top team and zeitgeistmovie.com as the top individual. One new prime was found by Fish. Thank you to all who participated and especially for your patience. We very much appreciate the support. For more stats and information, please see this forum thread.

2008-11-28: The Prime Time Challenge (Reloaded)

Four and a half hours into the Prime Time Challenge (Reloaded) and all is well. After a few minor bumps at the start, everything seems to be going smoothly. Most definitely this is the highest activity PrimeGrid has ever seen. :) Finally a good initiation for the new server. Thank you to everyone participating. Now let's find some primes!!! For more information, please see this forum thread.

2008-11-27: The Prime Time Challenge (Reloaded)

The pre-stress on the server to the Prime Time Challenge (Reloaded) has shown a substantial improvement. A few more adjustments should make things even better. Therefore, the Challenge is on for 28 Nov - 30 Nov. More information can be found in this forum thread.

2008-11-26: The Proth Prime Search

The first new "reportable" primes have started to trickle in. Congratulations to Kai Strang for finding the first one 825*2^373331+1...just in time for the Prime Time Challenge (28 Nov - 30 Nov). Come join the Challenge and find a prime for yourself. For more information, please see this forum thread.

2008-11-24: The Prime Time Challenge (Reloaded)

The Prime Time Challenge has been rescheduled for 28 Nov - 30 Nov. We would like to pre-stress the server on 27 Nov at 17:00 UTC. For more information, please see this forum thread.

2008-11-15: The Prime Time Challenge

While the Challenge has been canceled (will be rescheduled) we will continue keeping stats for the current dates (14-16 November). The reason for this is that we want to continue to stress the server so we can see the impact on different server related issues. This will help us better prepare for the Prime Time Challenge (Reloaded). :) For those who are interested, please continue to crunch Proth Prime Search LLR through 16 Nov 2008 18:00 UTC. The results will be unofficial but the process will help us greatly. Thanks for the consideration and again, we apologize for the cancellation.

2008-11-14: The Prime Time Challenge

The Prime Time Challenge has been canceled. While the server is fine, we are having issues that we are not yet able to resolve. We sincerely apologize for this. More information to come when we have it.

2008-11-13: The Prime Time Challenge

Less than 24 hours remain until the Prime Time Challenge (14-16 November 2008). The initiation process is already warming up as the load increases on the Proth Prime Search (LLR) in advance of the start. We are approaching the "reportable" level in Chris Caldwell's The Largest Known Primes Database! Come help us reach it and find a prime for yourself. For more information, please see this forum thread.

2008-11-09: The Prime Time Challenge

Less than a week remains until the 48hr Prime Time Challenge (14-16 November 2008). Come help us initiate the new server and maybe find a prime large enough to enter into Chris Caldwell's The Largest Known Primes Database! The Challenge will highlight PrimeGrid's newest project, the Proth Prime Search. For more information, please see this forum thread.

2008-11-01: Preparing for the Prime Time Challenge

The key to an effective prime search is having a good sieve file. For the past several months, our primary focus has been on getting the PPS Sieve deep enough to start LLRing. While we have made great strides in this effort, we still need more help. Leading up to this Challenge, anyone with a 64 bit multiple core system is encouraged to join the Proth Prime Search sieving effort. Please see this post if you are interested.

2008-10-31: The Prime Time Challenge

PrimeGrid's Challenge series continues with the Prime Time Challenge (14-16 November 2008). It's high time we initiated the new server and what better way to do it than with a Challenge. Also, it's time to return to the thrill of finding primes...and for that, we turn to PrimeGrid's newest project, the Proth Prime Search. Currently, these tests are rather short so this will also give us a good opportunity to "stress" test and fine tune the new server. The Proth Prime Search is slowly working its way up to the "reportable" prime level in Chris Caldwell's The Largest Known Primes Database! So please come join us as we initiate the new server and bring the Proth Prime Search to the "reportable" prime level. For more information, please see this forum thread.

2008-10-27: New server is live

While I'm writing these lines, the database is already running on the shiny new server in the new rack. While Murhpy has definitely played his role today, we hope that all troubles are gone and everything will be running smooth from now on. The first minutes seem promising, and the speed has improved significantly. We'll keep you posted. Big thanks for Willy for his work on the servers, and to all donators who helped make this server a reality!

2008-10-23: Scheduled downtime - new server installation!

We are planning a scheduled downtime of several hours on Monday, October 27. We will be relocating PrimeGrid and BOINCstats servers to the new rack, and will add a new server for PrimeGrid, which has been purchased using funds from the recent donation drive.

2008-10-03: "Optimal" sieve depth reached!

In a review yesterday of the Cullen/Woodall Project status, it was determined that we are at "optimal" sieve depth...actually, a little beyond it. Therefore, we are stopping the 32 bit and 64 bit Cullen/Woodall Sieve applications and archiving the sieve. Cullen/Woodall LLR will remain active up to n=10M. For more information, please see this forum post.

2008-10-01: Planned outage

We have just received a notice that the datacenter where PrimeGrid and BOINCstats are located are going to do planned maintenance on the electrical grid that is powering everything, so we will have an outage starting 23:00UTC. The outage is planned to last at least 3 hours. Sorry for the inconvenience; you may wish to cache a little more work this evening.

2008-09-30: 10P milestone reached at PSP Sieve!

During the completion of the Challenge and in the excitement of reaching the funds for a new server, the Prime Sierpinski Problem Sieve entered into the 10P range. This was our "soft" goal for PrimeGrid's one year anniversary (13 October 2008). We reached it two weeks ahead of time. Congratulations everyone on this AMAZING accomplishment. For more information about the Prime Sierpinski Problem and next year's sieve goal, please see this forum post.

2008-09-29: A new server is in PrimeGrid's future!

The Back to the Future Challenge has ended. Over 8000 Woodall WU's were completed by 204 teams and 1108 individuals. Congratulations to BOINCstats as the top team and lunarcom as the top individual. Also, thanks to the help of the anonymous donor as well as the hundreds of users who participated in the Challenge, we now have the funds to purchase a new server. For more stats and information, please see this forum post.

2008-09-27: Message from Anonymous Donor

With just over half a day left in the Back to the Future Challenge, we have a solid green bar on the donation page. Congratulations everyone!!! The matching funds have come in as well as a message from the anonymous donor. A special thank you goes out to this individual for ensuring the continued growth of PrimeGrid. Best of Luck to everyone as this Challenge draws to an end.

2008-09-24: The Back to the Future Challenge

Less than three days remain in the Back to the Future Challenge. There's still a battle for the top spot with BOINCstats holding off a fierce charge by the Canadians! :) Does either team have something up their sleeves for the last 72 hours? Only time will tell. Overall the Challenge is going well. We are almost to n=5.4M with a goal of 5.5M in sight. Additionally, donations are still being accepted for the new server. Currently, with the matching funds from the private donor, we have reached our goal. Any additional funds will go towards upgrading the server specs. A special thank you to everyone for helping out. Best of Luck in the next 72 hours.

2008-09-20: The Back to the Future Challenge

Half way through and this is by far the most highly contested Challenge yet. Most surprisingly are the new teams and individuals atop the leader boards. A job well done by everyone. We are currently at the n=5.30M level with a goal of reaching 5.5M by the end. The Back to the Future Challenge has also made progress in donations for the new server. With seven days left, we have reached 52.8% of the funds needed. With the matching funds offer from the private donor, we need to reach at least 66.1%...the donor will complete the rest. One PrimeGrid user has started her own mini challenge, Krazy Kenzie's Server Challenge. She's just one donor away from success. :) Please check it out and see if you can help her make the "right" decision.

2008-09-16: GIMPS set to claim $100,000 EFF award!!!

Congratulations to The Great Internet Mersenne Prime Search (GIMPS)! On August 23rd, a UCLA computer discovered the 45th known Mersenne prime, 2^43,112,609-1, a mammoth 12,978,189 digit number! The prime number qualifies for the Electronic Frontier Foundation $100,000 award for discovery of the first 10 million digit prime number. By the way, the second prime discovered less than two weeks later was also more than 10 million digits. It's the the 46th known Mersenne prime, 2^37,156,667-1, and comes in at 11,185,272 digits. For more information, please visit the GIMPS site.

2008-09-12: 45th and 46th Known Mersenne Primes Found!!!!

Congratulations to The Great Internet Mersenne Prime Search (GIMPS)! They have made extraordinary finds within two weeks of each other after going almost two years without a prime. We certainly marvel at this wonderful achievement. They are currently working on finding a suitable press outlet. More details will be announced early next week. The big question...is either one 10 million digits or more to claim the Electronic Frontier Foundation $100,000 award? :) For more information, please visit the GIMPS site. Again, congratulations!!!

2008-09-12: The Back to the Future Challenge

Less than 24 hours till the Back to the Future Challenge. Please come join us as we journey back to PrimeGrid's most successful project so far, the Woodall Prime Search, to help us prepare for the future. A private donor has made an anonymous "matching funds" offer matching all donations 1:1 made from now through the Challenge (13 Sept 18:00 UTC to 27 Sept 18:00 UTC) up to the total amount needed for the new server. For more information, please see this forum thread.

2008-09-06: The Back to the Future Challenge

PrimeGrid's Challenge series continues with the Back to the Future Challenge. We are very pleased and excited to announce that a private donor has made an anonymous "matching funds" offer. All donations made from now until the end of this Challenge (27 September) will be matched 1:1 (up to the total amount needed for the new server). Please come join us as we journey back to PrimeGrid's most successful project so far, the Woodall Prime Search, to help us prepare for the future. For more information, please see this forum thread.

2008-08-31: Prime for 321 Prime Search

We are still awaiting contact with the pre-Challenge 321 Prime Search prime finder. If no contact is made soon, the prime will be transferred over to anonymous. PrimeGrid user, LadyHawk_A321, please contact project administrator at admin@primegrid.com as soon as possible. For more information on the prime, please see this forum thread.

2008-08-25: The Dog Days of Summer Challenge

Sirius has retreated to the horizon, but he refuses to go into the night sky without a prime. While the Challenge is over, the Dog Days remain...so let's put Sirius to sleep by finding that prime. It will take another 3-6 days for most results to be paired and declared valid. Therefore, Challenge rankings will not be finalized until then. The WU deadline was set to 3 days so unpaired results should be cleaned up quickly. For those who are interested in helping clean up these results, just leave your machines crunching 321 LLR for another 3 days. For up-to-date information, please see this forum thread.

2008-08-24: The Dog Days of Summer Challenge

Less than 24 hours remain. Sirius refuses to go back to the night. The only thing that is known to work is by feeding him a prime. So let's find that prime and bring the Dog Days of Summer to an end. :D For more information, please see this forum thread.

2008-08-22: Server down and back up

PrimeGrid server was inaccessible for about 30 minutes because the network at the datacenter where PrimeGrid and BOINCstats are hosted was down. The datacenter technicians seem to have brought the network back up, but we have no idea if it's going to stay up (the support phones of the hosting provider are down). Update 18:11 UTC: it seems that the power was cut to the building; the servers were forcibly rebooted. I'm checking for stuck system processes now. Update 18:15 UTC: validator was stuck; it's fixed now. I think everything is running smooth now.

2008-08-21: The Dog Days of Summer Challenge

Less than 24 hours till the Dog Days of Summer Challenge . For more information, please see this forum thread.

2008-08-16: Prime for 321 Prime Search

The cooling rains have started early. In the run-up to the Dog Days of Summer Challenge, PrimeGrid's first 321 Prime Search prime has been discovered. Stay tuned for more details. UPDATE: 2008-08-18 We are still awaiting contact with prime finder.

2008-08-15: The Dog Days of Summer Challenge

Look yonder in the hot summer sky and you can see the clouds building. A storm is brewing in the distance...a storm to end the Dog Days of Summer. Please come join us in a 3 day (22-24 August - 72 hour) Challenge to usher an end to the hot sweltering days of summer. PrimeGrid's 321 Prime Search LLR application has been chosen. For more information, please see this forum thread.

2008-08-08: The Dog Days of Summer Challenge

PrimeGrid's Challenge series continues with the Dog Days of Summer Challenge. Please come join us in ushering an end to the hot sweltering days of summer. A 3 day (22-24 August - 72 hour) Challenge is being offered on PrimeGrid's 321 Prime Search LLR application. For more information, please see this forum thread.

2008-07-31: Riesel Sieve project information

For those of you wondering what is the problem with Riesel Sieve, here is a word from BOINC side administrator Bryan: Basically, the project creator has disappeared. People have been in contact with him, but we haven't heard any resumption date or even if things will resume. For the time being, I'm focusing my efforts on getting the non-BOINC side of the project up, as it is far easier and requires far less resources. We do not have access to any of the databases or we would have been able to restore things even without the project creator. Our wishes for RS to return as soon as possible.

2008-07-27: PSP finds Mega Prime

The Prime Sierpinski Project has discovered their second mega prime: 258317*2^5450519+1. It is 1640776 digits long and will rank as the 12th largest known prime. The project has now found 17 primes total. There are only 12 primes left to solve the Prime Sierpinski Problem. For more information, please see this forum post.

2008-07-22: Back online

Database has been recovered, please read a lengthy explanation in this forum thread.

2008-07-21: Database issues

We are having database issues...stay tuned for more information.

2008-07-21: The Lunar Landing Challenge

"Houston, Tranquility Base here. The Eagle has landed." The Lunar Landing Challenge is over. Over 525,000 WU's were completed by 193 teams and 1331 individuals. Congratulations to SETI.Germany as the top team and Banshee as the top individual. For more stats and information, please see this forum post.

2008-07-19: The Lunar Landing Challenge

T-plus 24 hours after liftoff and all systems are nominal. :) The start severely stressed the vehicle, but it eventually made it into orbit. 48 hours remain until the Lunar Landing. For more information, please see this forum thread.

2008-07-17: The Lunar Landing Challenge

T-minus 10 hours till liftoff and all systems are go. A 3 day (18-20 July - 72 hour) Lunar Landing Challenge is being offered on PrimeGrid's Prime Sierpinski Project sieve application. For more information, please see this forum thread.

2008-07-15: The Lunar Landing Challenge

T-minus 3 days and counting. Unlike NASA, there are no holds in this countdown! :) Please come join us in commemorating the 39th Anniversary of the lunar landing by Apollo 11. A 3 day (18-20 July - 72 hour) Lunar Landing Challenge is being offered on PrimeGrid's Prime Sierpinski Project sieve application. For more information, please see this forum thread.

2008-07-14: WU's lengthened

PrimeGrid is experiencing an increase in activity. In order to minimize the database AND to prepare for the upcoming Lunar Landing Challenge, sieve WU's have been lengthened. Credit has been adjusted accordingly. For more information, please see this post.

2008-07-10: Database issues

We are having database issues, stay tuned for more information. Update 5:38 UTC: the database has been brought back online.

2008-07-07: Server software upgrade

[edit] Upgrade completed way ahead of schedule at 11:40 UTC. I am upgrading server software, so the project is offline. Estimated time of upgrade completion - 13:00 UTC. After the upgrade is completed, I will update this newspost. Post any issues you think may be caused by the upgrade to this thread.

2008-07-06: The Lunar Landing Challenge

PrimeGrid's Challenge series continues with the Lunar Landing Challenge. Please come join us in commemorating the 39th Anniversary of the lunar landing by Apollo 11. A 3 day (18-20 July - 72 hour) Challenge is being offered on PrimeGrid's Prime Sierpinski Project sieve application. For more information, please see this forum thread.

2008-06-29: 3*2^n-1 switched to +1

We've switched 3*2^n-1 subproject, which has been completed to n=5M and had no more work, to 3*2^n+1. The tasks are significantly shorter now (in the range of minutes), but it will change quite rapidly as we progress through the test space.

2008-06-13: PrimeGrid's Birthday Challenge

The Birthday Party is over and all the candles have been blown out. Over 200,000 WU's were completed by 84 teams and 374 individuals. Congratulations to L'Alliance Francophone as the top team and Banshee as the top individual. For more stats and information, please see this forum post page.

2008-06-11: PrimeGrid's Birthday Challenge

Less than a day remains until the Birthday Challenge begins. We are celebrating PrimeGrid's 3rd Birthday with a 24 hour Challenge on the Twin Prime Search. Please check your local time zones to determine your exact Challenge time: 12 June 2008 00:00 UTC to 13 June 2008 00:00 UTC. For more information, please see this forum thread.

2008-06-07: PrimeGrid's Birthday Challenge

PrimeGrid's Challenge series continues with the Birthday Challenge. Please come join us in celebrating PrimeGrid's 3rd Birthday. A 24 hour Challenge is being offered on PrimeGrid's oldest active application, the Twin Prime Search. Hopefully we'll be able to give PrimeGrid a good present by finding the twin during the Challenge. :) For more information, please see this forum thread.

2008-06-01: The Drive for Five Challenge

The Checkered flag is out...and The Drive for Five Challenge has ended. 22512 WU's were completed by 255 teams and 1681 individuals. Congratulations to L'Alliance Francophone as the top team and Banshee as the top individual. Remember, the top 40 places earn points for this Challenge. For more stats and information, please see this forum post page.

2008-05-30: The Drive for Five Challenge

Less than 48 hours remain in the Challenge. For teams, places 1-4 are pretty much wrapped up. However, there is a tight 3-way battle for 5th place and several others beyond that. For individuals, there are many tight races below the top 3. Remember, due to the length of the Challenge, places 1-40 will earn Challenge Points this time. For more information, please see the Challenge Series page.

2008-05-23: The Drive for Five Challenge

Half way through the Challenge...and although an incredible amount of work has been accomplished, the numbers have the upper hand right now. 13020 WU's have been completed but 16036 remain. Our goal is still to reach n=5M. Therefore, we are hosting a sprint this weekend to see if we can get back even or maybe ahead of where we need to be in order to reach 5M by the end of 31 May. For more information, please see this forum post.

2008-05-16: The Drive for Five Challenge

24 hours into the Challenge and all is going well. 2100 WU's have been sent out and 26956 remain. Stats and more information can be found in this forum thread.

2008-05-14: The Drive for Five Challenge

Only 24 hours remain until The Drive for Five Challenge begins. Please check your local time zones to determine the start of the challenge: 15 May 2008 00:00 UTC. For more information, please see this forum thread.

2008-05-11: Updated application for TPS subproject - now has a screensaver!

New application version for TPS subproject has been released. If it behaves correctly, I will release it for other subprojects. For the first time, it also features a screensaver!

2008-05-09: The Drive for Five Challenge

PrimeGrid's Challenge series continues. Please come join our effort to reach n=5 million in the 321 Prime Search (3*2^n-1). The Challenge will begin 00:00 UTC, 15 May 2008. For more information, please see this forum thread.

2008-05-07: Problems saving preferences

We are aware of the issues saving your preferences (the message states that the changes have been saved, which doesn't actually happen), and are working to resolve the issue. It has been reported that logging out and in again helps, so you might try that as a workaround. UPDATE: as of 16:00 UTC preferences saving should work.

2008-04-30: Sieve WU lengths increased

In an attempt to lower the size of the database, we have increased the WU length to both the PSP Sieve and GCW Sieve projects. WU's are now 1.5X as long...so a 6 minute WU now takes 9 minutes. Credit has been adjusted accordingly.

2008-04-26: Workunit deadlines increased

The deadlines for subprojects that have very long workunits have been increased to 12 days. The subprojects affected are Woodall Prime Search, Cullen Prime Search, 321 Prime Search and Prime Sierpinski Project (all LLR).

2008-04-23: Standalone screensaver application published for testing

Nicolas has posted a standalone PrimeGrid screensaver application which is going to be included within the next science application update. We are looking for people to try it out on their computers so that we know it runs fine before we publish it project-wide. Visit the thread in the forums to find more about it.

2008-04-23: Can you survive for 24 hours without your computer?

It is obvious that without computers we would find our life extremely difficult, maybe even impossible. If they disappeared for just one day, would we be able to cope? Be part of one of the biggest global experiments ever to take place on the Internet. The idea behind Shutdown Day is to find out how many people can go without a computer for one whole day, and what will happen if we all participate! Shutdown your computer on 03 May 2008 and find out! Visit shutdownday.org and join the campaign! (And before you ask - no, PrimeGrid server isn't going down on that day)

2008-04-18: Mega Prime for 321 Search

On 23 Mar 2008 7:57:28 UTC, PrimeGrid, in collaboration with 321 Search, found another Mega Prime: 3*24235414-1 The prime is 1,274,988 digits long and enters The Largest Known Primes Database ranked 14th overall. This is 321 Search's first mega prime and 11th prime overall. It is the second largest found mega-digit prime using LLR. The discovery was made by Dylan Bennett of Canada using an Intel C2D @ 1.66 GHz with 2GB RAM. This computer took almost 15 hours and 30 minutes to complete the primality test. For more details, please see the official announcement. Decimal representation of the number is also available.

2008-04-17: Mega Prime for 321 Search

A PrimeGrid participant has discovered a Mega Prime for the 321 Search project. Stay tuned for more details.

2008-04-14: Updated statistics for prime finders

We have released an updated prime finder statistics page, which now counts primes find in all subprojects. The prime numbers are assigned a score which differs according to prime number size, so a giant Woodall prime is "worth" more than a smaller TPS prime. The next step in improving statistics is to show the participants all the primes that have been found, which isn't yet available in the current version, but is coming soon.

2008-04-14: Project Staging Area

After two months of testing, the Project Staging Area is officially open. This area was established to help prepare future projects for entry into PrimeGrid BOINC. It also offers a sneak peak into these projects by allowing users a chance to crunch them ahead of time. For more information, please see this forum thread.

2008-04-10: PSP finds Mega Prime

The Prime Sierpinski Project has discovered their first mega prime: 265711*2^4858008+1 (1462412 digits long). The project has now found 16 primes total. There are only 13 primes left to solve the Prime Sierpinski Problem. For more information, please see this forum thread.

2008-03-26: Up and running again

We are back up and running. For a detailed explanation of the events that caused the outage, please see the forum thread.

2008-03-22: PrimeGrid Database Issues

The aftermath of the Ides of March Challenge has taken its toll as the database has been experiencing issues since 20 March 2008. Conditions are slowly starting to improve. For more information, please see this forum thread.

2008-03-16: The Ides of March Challenge is Complete

Congratulations everyone on a job well done. The participation was well beyond our expectations. We exceeded our initial goal of 50K WU's and our advanced goal of 250K WU's downloaded. Additionally, we completed well beyond the sieve depth of p=2500T so a GREAT milestone for the Prime Sierpinski project and Seventeen or Bust. For more details on results, please see this forum post.

2008-03-15: The Ides of March Challenge Update

First 12 hours of the challenge have gone well! 186.1K WU's have been downloaded so far. Our original goal was 50K and that was hit 1 hour 35 minutes into the Challenge. Quite AMAZING!!! For an updated status, please see this forum post.

2008-03-14: The Ides of March Challenge Update

Less than 10 hours until the Ides of March. There has been an unprecedented run-up before the Challenge. We can sense the impending doom for 1000's of k/n pairs. For updated information, please see the forum thread.

2008-03-12: The Ides of March Challenge Update

Only 3 days remain until the Ides of March. Please check you local time zones to determine the start of the challenge: 15 March 2008 00:00 UTC. For updated information, please see the forum thread.

2008-03-08: The Ides of March Challenge

With the Ides of March just a week away, we wish to offer a challenge. Come join a one day effort in an attempt to push the Prime Sierpinski Sieve to over 50,000 WU's in one day and thus reach the p=2500T sieve depth. For more information, please see the forum thread.

2008-03-02: 64bit Linux sr2sieve

A 64bit Linux sr2sieve application has been released for the Prime Sierpinski Problem sieve. For more information, please see the forum post.

2008-02-27: Upcoming Projects

PrimeGrid will soon be offering three new projects. For more information about these and future considerations, please see the forum thread.

2008-02-20: Problems with 64bit Windows PSP Sieve fixed

Version 1.04 of PSP Sieve application has been released, fixing the issue with 64bit Windows hosts.

2008-02-19: Problems with 64bit Windows PSP sieve application

We have temporarily disabled 64bit Windows PSP Sieve application because it was crashing and locking up BOINC client. We are investigating the cause for that; for now 32bit application will be sent instead.

2008-02-18: 64bit Linux gcwsieve

I know some of you were eagerly awaiting this. Well, the time has come - we now started testing 64bit Linux gcwsieve application. For more information, see the forum thread.

2008-02-15: End of the life cycle of primegen application

We are inserting the final batches of work for our oldest available application, primegen. While primegen has proved to be very useful in the early project stages for infrastructure testing, it has served it's purpose and it's time to make way for newer, more efficient applications. Once the final batches are completed the cleanup will be executed, finally removing old stuck workunits. We suggest participants running primegen exclusively also select an additional subproject for future processing. Sieve subprojects are very similar to primegen in size, so it is probably a good choice. Once there are no more primegen work to send, we will update project for such participants to select sieve subprojects.

2008-01-31: Unscheduled outage

PrimeGrid is down for a moment, because workunit table has crashed; the repair process is running right now. Thanks to Lennart from Sweden who called me on the phone and told about the problem. Update 14:22 UTC: We're back up.

2008-01-10: TPS work available again

Twin prime search work is available again (we had a few days outage for this subproject because work supply went dry).

2007-12-29: Record breaking Woodall prime

On 21 Dec 2007, 10:09:30 UTC, PrimeGrid's Woodall Prime Search found the 33rd and largest known to date Woodall prime: 3752948*23752948-1 The prime is 1,129,757 digits long and enters The Largest Known Primes Database ranked 1st for Woodall primes and 13th overall. It's the first found mega-digit prime using LLR. The discovery was made by Matthew J. Thompson of the United States using an Intel P4 @ 2.8 GHz with 512MB RAM. This computer took almost 15 hours and 11 minutes to complete the primality test.

2007-12-28: 1 million digit prime

A user of PrimeGrid has discovered a Woodall prime which is over 1 million digits long. It is the biggest Woodall prime ever discovered, and 13th biggest known prime of any kind. Stay tuned for more details.

2007-12-16: Code upgrade

Server backend code has been upgraded, the option to decline team founder transfer now works. If you notice any errors (no, dozens of buttons in the forum is not an error), please post in the forums or use the contact link available in every page in the very bottom.

2007-12-09: Scheduled downtime

During the night of December 14/15 (Europe time) PrimeGrid server will be down because of scheduled maintenance in the datacenter where PrimeGrid and BOINCstats are hosted. The downtime is needed to upgrade power infrastructure, because currently there isn't enough backup power (UPS) to run all the servers in case of a power outage.

2007-12-05: New subproject available

We have released the LLR application for the 321 Search. 321 is attempting to find a mega prime in the form 3*2^n-1. The 4+ year old project currently holds the largest non-GIMPS/non-Seventeen or Bust prime. As usual, you can choose to crunch work for this project by visiting your project preferences page. Supported platforms: 32bit Linux & Windows.

2007-12-05: Unexpected outage (resolved)

Results table has crashed, the project is offline while we recover data. Update: the issue has been resolved at 8:57 UTC.

2007-10-30: Automatic reporting to the Prime Pages available

From now on you can give permission to PrimeGrid to report the primes you find to the Prime Pages on your behalf. To do this, go to the project preferences page and enter your data.

2007-10-27: Backend code upgrade

The backend code has been upgraded. There were some issues related to the web code, but they seem to be fixed. If you find any problems that I missed, please post in the forums.

2007-10-14: Linux LLR available!

Good news for Linux lovers - with the help from our user Der Meister we have released 32bit Linux LLR application for Twin Prime Search project. If it goes well, it will be released for Cullen/Woodall Prime Search, too. The 32bit application is also being sent to 64bit hosts.

2007-10-13: Prime Sierpinski Project sieve available

We have released Sieve application for Prime Sierpinski Project. It is trying to solve the Prime Sierpinski Problem. Windows 32bit and 64bit versions are supported. As usual, you can choose to crunch work for this project by visiting your project preferences page.

2007-09-30: LLR Cullen percentage reporting bug fixed

Thanks to Bryan from Riesel Sieve, the Cullen workunit progress reporting bug has been fixed. The workunits running application version 5.08 should correctly display feedback during processing.

2007-09-29: 64bit sieving application available

A 64bit Windows version of GCW sieve application has been released. It improves speed twice comparing to 32bit version. The new application is automatically sent to hosts running 64bit version of BOINC that have sieving subproject enabled in the project preferences.

2007-09-15: Cullen/Woodall Sieve available

We have released a sieving app for Cullen/Woodall Prime Search. Sieving will help to greatly reduce the amount of probable primes, therefore speeding up the actual prime search. You can choose to run sieve application by visiting project preferences page; please have in mind that the application has just been released, so it may have bugs or issues (although we haven't noticed any). Supported platforms: Windows 2000/XP/2003/Vista.

2007-09-03: Record Woodall prime number found... again!

On 20 Aug 2007, 2:40:57 UTC, PrimeGrid's servers returned a positive result in the Woodall Prime Search. It was the double check validating that a Woodall prime was found on 13 Aug 2007, 1:42:08 UTC. 2367906*22367906-1 This is the 32nd and largest known to date Woodall prime. It is 712818 digits long and enters The Largest Known Primes Database (http://primes.utm.edu/primes/) ranked 1st for Woodall primes and 25th overall. The discovery was made by Stephen Kohlman of Canada using an Intel C2D 6300 @ 1.86 GHz with 1 GB RAM. This computer took a little over 5 hours and 41 minutes to test using the LLR program. Stephen is a member of Canada team.

2007-09-03: Leaving to Geneva

I will be leaving to Geneva for BOINC Workshop early tomorrow morning. This means that the project will have to run unattended for almost a week (I will of course monitor the server, but my time will be limited, so don't expect quick fixes if something dies).

2007-08-25: Message to participant "Owner"

Message to project participant known as "Owner" or "big steve": please contact project administrator at admin@primegrid.com. Your computer has made a significant discovery, and we want to know your details before we publicize it.

2007-08-19: Network maintenance

Tonight at 0:00UTC network maintenance will be performed in the datacenter where PrimeGrid server is hosted. The maintenance is planned to last approximately 30 minutes, during it the access to the project might be slow or unavailable. Sorry for the inconvenience.

2007-08-09: Record Woodall prime number found

On 7 Aug 2007, 15:25:07 UTC, PrimeGrid's servers returned a positive result in the Woodall Prime Search. It was the double check validating that a Woodall prime was found on 4 Aug 2007, 19:36:57 UTC. 2013992*22013992-1 The prime is 606279 digits long and enters The Largest Known Primes Database (http://primes.utm.edu/primes/) ranked 1st for Woodall primes and 37th overall. The discovery was made by Lasse Mejling Andersen of Denmark using an Intel Celeron 2.80 GHz with 512 MB RAM. This machine took a little over 3 hours and 27 minutes to test using the LLR program. For more details, please see here.

2007-08-08: Biggest ever Woodall prime discovered!

A few minutes ago PrimeGrid validated a workunit that had discovered the biggest Woodall prime ever discovered. More information will follow up later.

2007-08-06: Validation suspended

Validation of returned results may be slow or even temporarily suspended while we sort the problems that appeared because of software upgrade. All credit will be granted, no work is lost.

2007-08-04: Statistics moved

Stats sites should update references to PrimeGrid stats - filenames have changed because of recent code update.

2007-08-03: Maintenance extended

The maintenance has been extended because of issues getting new work.

2007-08-02: Shutdown for maintenance

PrimeGrid will be shut down for major software upgrade on August 3rd, 15:00UTC. The outage will last at least 4 hours, but may well be extended up to 48 hours.

2007-07-03: New subproject added

We have added a new prime search project, Cullen/Woodall prime search. These primes are of forms n*2n+1 and n*2n-1 respectively. Our goal is to find the biggest Cullen and Woodall primes ever. This isn't as easy as it may sound, only 14 Cullen primes and 30 Woodall primes have ever been found, however, we believe that PrimeGrid has sufficient computing power to make this search plausible. It is now possible to choose the subprojects you would like to run in project preferences page. Please note that when you are using account managers your choice may be reset when changing resource share allocation.

2007-06-15: Twin Prime Search progress

Our user Terminal has been collecting statistics about our progress in the current Twin Prime Search project. Please see this thread for more information.

2007-06-06: 10 million workunits sent

Today marks the day when 10 millionth workunit was issued in the project. While this is nothing more than a simple numeric milestone, it is a really nice number to reach in the project that is all about numbers. The workunit was crunched by the computer owned by user Strelnieks. Congratulations!