PrimeGrid’s321 Prime Search
On 24 Apr 2010 11:40:07 UTC, PrimeGrid’s 321 Prime Search found another Mega
Prime:3*26090515-1
The prime is 1,833,429 digits long and will enter Chris Caldwell's “The Largest
Known Primes Database” (http://primes.utm.edu/primes) ranked 17th overall. Thisis the second mega prime for the 3*2^n-1 form, and it is the third largest foundmega-digit prime using LLR.
The discovery was made by David Mumper of the United States using an AMD
Quad-Core Opteron 2378 with 8 GB RAM running Linux. This computer took
just over 15 hours and 24 minutes to complete the primality test. David is amember of the SETI.USA team.
The prime was verified on 26 Apr 2010 1:17:07 UTC, by Rintaro Yoshinaka of Japan
using an Intel Core2 Duo E8400 @ 3.00GHz with 2 GB RAM running Windows XP.
This computer took about 8 hours to complete the primality test. Rintaro is amember of Team 2ch.
Credits for the discovery are as follows:
1. David Mumper (United States), discoverer
2. PrimeGrid, et al.
3. Srsieve, sieving program developed by Geoff Reynolds
4. 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=92517
Using a single core PC would have taken decades to find this prime. So this timely
discovery would not have been possible without the thousands of volunteers whocontributed their spare CPU cycles. A special thanks to everyone who contributed
their advice and/or computing power to the search.
This is PrimeGrid’s 8th mega prime. The 321 Prime Search will continue to seek
even larger primes. To join the search please visit PrimeGrid:
http://www.primegrid.com

PrimeGrid’s
321 Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius, which
utilizes BOINC and PRPNet to search for primes. PrimeGrid's primary goal is to bringthe excitement of prime finding to the "everyday" computer user. Simply download
the software and let your computer do the rest. Participants can choose from avariety of prime forms to search. With a little patience, you may find a large oreven record breaking prime.
BOINC
The Berkeley Open Infrastructure for Network Computing (BOINC) is asoftware platform for distributed computing using volunteered computerresources. It allows users to participate in multiple distributed computing
projects through a single program. Currently BOINC is being developed by ateam based at the University of California, 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
specifically designed 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, but relies 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