PrimeGrid’s
321 Prime Search
On 23 Mar 2008 7:57:28 UTC, PrimeGrid, in collaboration with 321 Search, foundanother Mega Prime:

3*24235414-1
The prime is 1,274,988 digits long and will enter Chris Caldwell's “The Largest
Known Primes Database” (http://primes.utm.edu/primes) ranked 14th overall. This is
321 Search’s first mega prime and 11th prime overall. It is the second largest foundmega-digit prime using LLR.
The discovery was made by Dylan Bennett of Canada using an Intel C2D @ 1.66
GHz with 2 GB RAM running Linux. This computer took almost 15 hours and 30
minutes to complete the primality test.
The prime was verified on 2 Apr 2008 5:13:16 UTC, by Dave Pickles of Canada
using an AMD Athlon XP 2500+ with 512 MB RAM running Windows 2000.
This computer took 18 hours 42 minutes to complete the primality test.
The credits for the discovery are as follows:

1. Dylan Bennett (Canada), discoverer
2. 321 Search
3. PrimeGrid, et al.
4. Srsieve, sieving program developed by Geoff Reynolds
5. NewPGen, sieving program developed by Paul Jobling
6. 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=84769
This is PrimeGrid’s second mega prime and first 321 prime. Since the searchbegan, just over 74108 tests have been completed by 4331 users using 7454
computers.
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 whocontributed their spare CPU cycles. A special thanks to everyone who contributed
their advice and/or computing power to the search - especially Paul Underwood andthe entire 321 Search community (http://www.mersenneforum.org/321search/).
PrimeGrid’s 321 Prime Search will continue to search for even larger primes. To join
the search please visit PrimeGrid: http://www.primegrid.com

PrimeGrid’s
321 Prime Search
About PrimeGrid
Rytis Slatkevicius, the developer of PerlBOINC - a Perl-language-based port of the
BOINC platform, created PrimeGrid as a test project for PerlBOINC. PrimeGrid’s first
sub-project was in cryptography as it participated in the RSA Factoring Challenge.
While it no longer participates in the challenge, PrimeGrid continues to expand itsfunctionality. Currently the project is running the following sub-projects:••••Twin Prime Search: searching for gigantic twin primes of the form k*2n + 1
and k*2n - 1.
Cullen-Woodall Search: searching for mega primes of forms n*2n + 1 andn*2n - 1.
3*2^n-1 Search: searching for mega primes of the form 3*2n - 1.
Prime Sierpinski Project: helping Prime Sierpinski Project solve the Prime
Sierpinski Problem.

For more information, please visit PrimeGrid: http://www.primegrid.com
About 321 Search321 Search began in February 2003 from a post by Paul Underwood seeking help
from interested parties in a prime search attempt of the form 3*2^n-1. The initial
goal was to build upon the completed work at http://www.prothsearch.net andextend the list of known primes to an exponent of 1 million. Interests gathered
quickly and by the time they reached n=1 million, they had already pre-sieved
further.
At that time, using George Woltman's libraries which implemented the newly
discovered method of IBDWT (irrational base discrete weighted transform)
multiplication of Colin Percival, Jean Penne's LLR (Lucas-Lehmer-Riesel) computer
program gave them a rate boost of 400%. This together with computer hardware
advances allowed them to reach tests at 1 million digits or exponent of about 3.3
million within a few years, with stated aim of eventually finding a mega-prime.
A note from Paul Underwood
In the early days, 321 Search relied on word of mouth at Yahoo groups torecruit people, but soon were kindly invited by Mike Vang a.k.a. “Xyzzy” tohave their own sub forum at http://www.mersenneforum.org. There wecongregated to discuss the search and to develop a few administration
scripts for such things as participant point statistics and reservations. All thiswas manually maintained until we joined forces with PrimeGrid who had aproper server using BOINC (Berkeley Open Infrastructure for NetworkComputing.)
I see the future of the search for “321 primes” dependent on PrimeGrid,
because the administration is relatively minimal and the double checking
done by them highly limits computation errors, which increase with everlarger tests; plus it is easy for a contributor to link to and use the server. ThePrimeGrid’s
321 Prime Searchoriginal band of 321 Search will remain in existence for the foreseeable futuretoo.
I cannot thank enough all of the people who have helped -- with discussion,
administration and computer resources.
Paul Underwood
For more information, please visit 321 Search: http://www.mersenneforum.org/321search/
About BOINC
BOINC (Berkeley Open Infrastructure for Network Computing) is a software platform
for distributed computing using volunteered computer resources. It allows users toparticipate in multiple distributed computing projects through a single program.
Currently BOINC is being developed by a team based at the University of California,
Berkeley led by David Anderson.
For more information, please visit BOINC: http://boinc.berkeley.edu