PrimeGrid’s
Generalized Fermat Prime Search
On 20 Jun 2012, 4:26:47 UTC, PrimeGrid’s Generalized Fermat Prime Search found thelargest known Generalized Fermat mega prime:356926524288+1
The prime is 2,911,151 digits long and enters Chris Caldwell's “The Largest Known
Primes Database” (http://primes.utm.edu/primes) 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 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 amember of the Don't Panic Labs team.
The PRP was confirmed prime by an Intel Core i7 2600k @ 3.4Ghz with 8 GB RAM,running Windows 7 x64. This computer took 88 hours 19 minutes to complete theprimality test using LLRx64. Prior to LLR’s completion, an additional PRP test wasconducted using GenefX64. This test took 25 hours 34 minutes to complete.
Because the primary finder failed to claim the prime, credit at the Prime Pages has been
given to the double checker. Therefore, credits for the discovery are as follows:
1. (bherbihyewrbg) (Japan), discoverer
2. Tim McArdle (United States), double checker
3. PrimeGrid, et al.
4. AthGFNSieve, sieve program developed by David Underbakke
5. GenefX64, probable prime program developed by David Underbakke6. GeneferCUDA, probable prime program developed by Shoichiro Yamada
7. LLR, primality program developed by Jean Penné
Entry in “The Largest Know Primes Database” can be found here:
http://primes.utm.edu/~caldwell/primes/page.php?id=108492
This is the 3rd known GFN prime at N=524288. Using a single PC would have taken
years to find this prime. So this timely discovery would not have been possible without
the hundreds of volunteers who contributed their spare CPU cycles. A special thanks toeveryone who offered their advice and/or computing power to the search - especiallyDavid Underbakke, Mark Rodenkirch and Geoff Reynolds who were major forces inmoving the project forward. Also, thank you to all the sievers, especially Honza Cholt.
This is PrimeGrid’s 27th mega prime. The Generalized Fermat Prime Search willcontinue to seek even larger primes. To join the search please visit PrimeGrid:
http://www.primegrid.com

PrimeGrid’s
Generalized Fermat Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius, Lennart
Vogel, and John Blazek, which utilizes BOINC and PRPNet to search for primes.
PrimeGrid's primary goal is to bring the excitement of prime finding to the "everyday"
computer user. Simply download the software and let your computer do the rest.
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.
BOINC
The Berkeley Open Infrastructure for Network Computing (BOINC) is a software
platform for distributed computing using volunteered computer resources. It allows
users to participate in multiple distributed computing projects through a singleprogram. Currently BOINC is being developed by a team based at the University ofCalifornia, Berkeley led by David Anderson.
This platform currently supports projects from biology to math to astronomy. For
more information, please visit BOINC: http://boinc.berkeley.edu
PRPNet
PRPNet is a client/server application written by Mark Rodenkirch that is specificallydesigned to help find prime numbers of various forms. It is easily ported between
various OS/hardware combinations. PRPNet does not run each PRP test itself, butrelies on helper programs, such as LLR, PFGW, phrot, and genefer to do the work.
For more information, please visit PrimeGrid’s PRPNet forum thread:
http://www.primegrid.com/forum_thread.php?id=1215
For more information about PrimeGrid and a complete list of available prime search
projects, please visit: http://www.primegrid.com