PrimeGrid’sProth Prime Search	  On 4 Jan 2012 0:34:57 UTC, PrimeGrid's Proth Prime Search project found a primeFermat divisor:
329*21246017 +1 Divides F(1246013)
The prime is 375,092 digits long and will enter Chris Caldwell's "The Largest Known
Primes Database" (http://primes.utm.edu/primes) ranked 6th for prime Fermat divisors
and 522nd. It is the 1st divisor found in 2012 and 293rd overall.
The discovery was made by Bruce Dodson of the United States using an Intel Xeon MP@ 2.80GHz with 12 GB RAM running Linux. This computer took just over 3 hours and 25
minutes to complete the primality test using LLR. Bruce is a member of theSicituradastra. team.
The prime was verified on 6 Jan 2012 17:41:07 UTC, by Ovidiu Cioca of Canada using
an Intel Core2 6700 @ 2.66GHz with 4 GB RAM running Windows XP. This computer
took 29 minutes and 45 seconds to complete the primality test using LLR.
The credits for the discovery are as follows:
1.
2.
3.
4.
5.
6.

Bruce Dodson (United States), discoverer
PrimeGrid, et al.
Srsieve, sieving program developed by Geoff Reynolds
PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
LLR, primality program developed by Jean Penné
OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron withmaintenance and improvements by Mark Rodenkirch

Entry in “The Largest Know Primes Database” can be found here:
http://primes.utm.edu/primes/page.php?id=103866
Fermat number divisibility (including generalized and extended) was checked by
OpenPFGW using the following settings: -gxo –a2 329*2^1246017+1. For more
information about Fermat and generalized Fermat number divisors, please see WilfridKeller's sites:••

http://www.prothsearch.net/fermat.html
http://www1.uni-hamburg.de/RRZ/W.Keller/GFNfacs.html

There were no generalized or extended generalized Fermat number divisors.
Using a single PC would have taken years to find this prime. So this timely discovery
would not have been possible without the thousands of volunteers who contributed theirspare CPU cycles. A special thanks to everyone who contributed their advice and/or
computing power to the search - especially all the sievers who work behind the scenes
to make a find like this possible.
This is PrimeGrid’s 9th prime Fermat divisor. The Proth Prime Search will continue tosearch for more primes. To join the search, please visit PrimeGrid:
http://www.primegrid.com

PrimeGrid’s
Proth 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
PRPNetPRPNet 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, wwww, 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