About
PrimeGrid's primary goal is to bring the excitement of prime finding to the "everyday" computer user. By simply
downloading and installing BOINC and attaching to the PrimeGrid project,
participants can choose from a variety of prime forms to search. With a little patience, you may find a large or even record
breaking prime and enter into Chris Caldwell's The Largest Known Primes Database as
a Titan!
PrimeGrid's secondary goal is to provide relevant educational materials about primes. Additionally, we wish to contribute to the
field of mathematics.
Lastly, primes play a central role in the cryptographic systems which are used for computer security. Through the study of prime
numbers it can be shown how much processing is required to crack an encryption code and thus to determine whether current
security schemes are sufficiently secure. PrimeGrid is currently running several sub-projects:
- 321 Prime Search: searching for
mega primes of the form 3·2n±1.
- Cullen-Woodall Search: searching for
mega primes of forms n·2n+1 and
n·2n−1.
- Prime Sierpinski Project: helping Prime Sierpinski Project solve the prime Sierpinski Problem.
- Proth Prime Search: searching for primes of the form k·2n+1.
- Seventeen or Bust: helping to solve the Sierpinski Problem.
- Sophie Germain Prime Search: searching for primes p and 2p+1.
- The Riesel problem: helping to solve the Riesel Problem.
- Generalized Fermat Prime Search: searching for primes of the form b2n+1.
Recent Significant Primes
On 28 Feb 2012 UTC, 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 1 st for Primorial primes and 253 rd 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.
Official announcement to come.
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 34 th overall. This is PrimeGrid's 23 rd 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 information, please see the Official announcement.
On 25 Feb 2012, 06:34:08, 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 28 th overall. This is PrimeGrid's 22 nd mega prime.
The discovery was made by Timothy D. Winslow ( Pooh Bear 27) of the United States
using an Intel Core i7 920 @ 2.8GHz with 12 GB RAM running Windows 7 Home Premium x64. 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 information, please see the Official announcement.
Other significant primes
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News 
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) application¦ends 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.
2 May 2012 | 19:14:19 UTC
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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.
23 Apr 2012 | 18:19:01 UTC
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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.
23 Apr 2012 | 1:10:46 UTC
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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.
17 Apr 2012 | 1:36:06 UTC
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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.
11 Apr 2012 | 21:09:00 UTC
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