About
PrimeGrid's primary goal is to advance mathematics by enabling everyday computer users to contribute their system's processing power towards prime finding. By simply
downloading and installing BOINC and attaching to the PrimeGrid project,
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 and enter into Chris Caldwell's The Largest Known Primes Database with a multi-million digit prime!
PrimeGrid's secondary goal is to provide relevant educational materials about primes. Additionally, we wish to contribute to the
field of mathematics.
Lastly, primes play a central role in the cryptographic systems which are used for computer security. Through the study of prime
numbers it can be shown how much processing is required to crack an encryption code and thus to determine whether current
security schemes are sufficiently secure. PrimeGrid is currently running several sub-projects:
- 321 Prime Search: searching for
mega primes of the form 3·2n±1.
- Cullen-Woodall Search: searching for
mega primes of forms n·2n+1 and
n·2n−1.
- Generalized Cullen-Woodall Search: searching for mega primes of forms n·bn+1 and
n·bn−1 where n + 2 > b.
- Extended Sierpinski Problem: helping solve the Extended Sierpinski Problem.
- Generalized Fermat Prime Search: searching for
megaprimes of the form b2n+1.
- Prime Sierpinski Project: helping the Prime Sierpinski Project solve the Prime Sierpinski Problem.
- Proth Prime Search: searching for primes of the form k·2n+1.
- Fermat Divisor Search: a subset of the Proth Prime Search specificically searching for divisors of
Fermat numbers.
- Seventeen or Bust: helping to solve the Sierpinski Problem.
- Sierpinski/Riesel Base 5: helping to solve the Sierpinski/Riesel Base 5 Problem.
- Sophie Germain Prime Search: searching for primes p and 2p+1.
- The Riesel problem: helping to solve the Riesel Problem.
- AP27 Search: searching for record length arithmetic progressions of primes.
Recent Significant Primes
On 13 December 2020, 16:07:34 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:
45·27661004+1
The prime is 2,306,194 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 77 th overall.
The discovery was made by Tim Terry ( TimT) of the United States using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 32GB RAM, running Linux Fedora.
This computer took about 1 hour, 10 minutes to complete the primality test using LLR2. Tim Terry is a member of the Aggie The Pew team.
For more information, please see the Official Announcement.
On 6 December 2020, 02:07:48 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:
15·27619838+1
The prime is 2,293,801 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 78 th overall.
The discovery was made by an anonymous user of China using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition.
This computer took about 2 hours to complete the primality test using LLR2.
For more information, please see the Official Announcement.
On 18 November 2020, 05:40:34 UTC, PrimeGrid's 27121 Prime Search through PRPNet found the Mega Prime:
121·29584444+1
The prime is 2,885,208 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 60 th overall.
The discovery was made by James Winskill ( Aeneas) of New Zealand using an Intel Xeon(R) E5-2637 v3 CPU @ 3.50GHz with 64GB RAM, running Microsoft Windows Server 2012 R2.
This computer took about 13 hours, 49 minutes to complete the primality test using LLR. James Winskill is a member of the PrimeSearchTeam team.
The prime was verified internally on 18 Nov 2020, 16:42:00 UTC, by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16 GB RAM, running Linux Gentoo. This computer took a little over 1 hour 42 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
Other significant primes
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News 
Good Riddance 2020! Challenge starts January 14th
The first challenge of the 2021 Series will be a 5-day challenge celebrating the end of the abomination which was the year 2020. The challenge will be offered on the PPS-DIV (LLR) application, beginning 14 January 00:00 UTC and ending 18 January 23:59 UTC.
To participate in the Challenge, please select only the Fermat Divisor Search LLR (PPS-DIV) project in your PrimeGrid preferences section.
Comments? Concerns? Discuss on the forum post for this challenge. Best of luck!
11 Jan 2021 | 17:08:37 UTC
· Comment
Another DIV Mega Prime!
On 13 December 2020, 16:07:34 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:
45*2^7661004+1
The prime is 2,306,194 digits long and enters Chris Caldwell's “The Largest Known Primes Database” ranked 77th overall.
The discovery was made by Tim Terry (TimT) of the United States using an Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz with 32GB RAM, running Linux Fedora. This computer took about 1 hour, 10 minutes to complete the primality test using LLR2. Tim Terry is a member of the Aggie The Pew team.
For more details, please see the official announcement.
10 Jan 2021 | 15:33:02 UTC
· Comment
DIV Mega Prime!
On 6 December 2020, 02:07:48 UTC, PrimeGrid's Fermat Divisor Search found the Mega Prime:
15*2^7619838+1
The prime is 2,293,801 digits long and enters Chris Caldwell's “The Largest Known Primes Database” ranked 78th overall.
The discovery was made by an anonymous user of China using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 hours to complete the primality test using LLR2.
For more details, please see the official announcement.
10 Jan 2021 | 15:28:20 UTC
· Comment
Change in Prime Reporting Procedure
With the release of LLR2, we are seeing a dramatic increase in the number of primes found by users that don't give permission to report them. To decrease the number of primes stuck waiting for permission to report that we never receive, we will still wait nineteen days for the first prime found by a user, but only seven days for subsequent primes before moving to the double checker or reporting as anonymous.
If you have primes reported to T5K through PrimeGrid already or have given permission to report and provided your name, this doesn't affect you. Otherwise, I strongly encourage you to change your PrimeGrid preferences to give permission.
27 Dec 2020 | 1:12:01 UTC
· Comment
Great Conjunction Challenge starts December 21
The ninth and final challenge of the 2020 Series will be a 10-day challenge marking the extraordinarily rare astronomical event known as the Great Conjunction. The challenge will be offered on the GFN-18, GFN-19, and GFN-20 subprojects, beginning 21 December 13:22 UTC and ending 31 December 13:22 UTC.
To participate in the Challenge, please select only the GFN-18 and/or GFN-19 and/or GFN-20 subprojects in your PrimeGrid preferences section.
Addendums? Annotations? Apprehensions? Discuss in the forum thread for this challenge. Best of luck!
18 Dec 2020 | 17:49:56 UTC
· Comment
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Newly reported primes(Mega-primes are in bold.)
7545*2^3345355+1 (zombie67 [MM]); 9989*2^1613357+1 (t-uhyo); 5897424691917*2^1290000-1 (vaughan); 5905049873247*2^1290000-1 (Sean); 5904831430767*2^1290000-1 (Ossi Mauno); 217604272^32768+1 (Tomiticus); 217565494^32768+1 ([AF>Occitania] f11ksx); 5900637369597*2^1290000-1 (vaughan); 217490378^32768+1 (B2lee); 5903468527227*2^1290000-1 (j.sheridan); 5901371924175*2^1290000-1 (jubdo); 5897231521977*2^1290000-1 (vino); 1533*2^1613132+1 (Homefarm); 217267202^32768+1 (Renix); 217265374^32768+1 ([AF>Occitania] f11ksx); 31*2^8348000+1 (A1ex01); 5894906201037*2^1290000-1 (Grebuloner); 5897785920297*2^1290000-1 (NerdGZ); 5894258272947*2^1290000-1 (Buckeye4lf); 217085704^32768+1 (Kellen) Top Crunchers:Top participants by RAC | Top teams by RAC |
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