PrimeGrid’s
Generalized Fermat Prime Search
On 8 Aug 2012, 8:58:58 UTC, PrimeGrid’s Generalized Fermat Prime Search found thelargest known Generalized Fermat mega prime:475856524288+1
The prime is 2,976,633 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 Masashi Kumagai 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 of the United States using an Intel Core i72600 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 ofthe Turan@BOINC 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 70 hours 48 minutes to complete theprimality test using LLRx64.
The credits for the discovery are as follows:

1. Masashi Kumagai (Japan), discoverer
2. PrimeGrid, et al.
3. AthGFNSieve, sieve program developed by David Underbakke
4. GFNSvCUDA , sieve program developed by Anand Nair
5. GenefX64, probable prime program developed by David Underbakke
6. 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/primes/page.php?id=108818
This is the 4th 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 Choltand Jim Breslin. A final thanks to Michael Goetz for porting GeneferCUDA to BOINC.
This is PrimeGrid’s 28th 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’sGeneralized 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