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 as
a Titan!
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.
- 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 Prime Sierpinski Project solve the Prime Sierpinski Problem.
- Proth Prime Search: searching for primes of the form k·2n+1.
- 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.
Recent Significant Primes
On 24 December 2019, 08:20:15 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
3214654524288+1
The prime is 3,411,613 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 3 rd for Generalized Fermat primes and 30 th overall.
The discovery was made by Alen Kecic ( Freezing) of Germany
using an NVIDIA GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition.
This computer took about 51 minutes to probable prime (PRP) test with GeneferOCL3.
Alen is a member of the SETI.Germany team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 32GB RAM, running Windows 10 Professional x64 Edition.
This computer took about 1 day, 1 hour and 45 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 24 December 2019, 01:28:13 UTC, PrimeGrid's Extended Sierpinski Problem found the Mega prime:
99739·214019102+1
The prime is 4,220,176 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 20 th overall.
This find eliminates k=99739; 9 k's remain in the Extended Sierpinski Problem.
The discovery was made by Brian D. Niegocki ( Penguin) of the United States
using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu.
This computer took about 14 hours and 14 minutes to complete the primality test using multithreaded LLR.
Brian is a member of the Antarctic Crunchers team.
For more information, please see the Official Announcement.
On 5 December 2019, 08:39:29 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
9125820262144+1
The prime is 1,824,594 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 14 th for Generalized Fermat primes and 82 nd overall.
The discovery was made by Yoshimitsu Kato ( yoshi) of Japan
using an NVIDIA GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10.
This computer took about 22 minutes to probable prime (PRP) test with Genefer OCL2.
Yoshimitsu Kato is a member of Team JPN.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition.
This computer took about 16 hours, 30 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 6 November 2019, 11:59:08 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
8883864262144+1
The prime is 1,821,535 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 14 th for Generalized Fermat primes and 80 th overall.
The discovery was made by Rod Skinner ( rjs5) of the United States
using an NVIDIA GeForce RTX 2080 Ti in an Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz with 63GB RAM, running Linux Fedora.
This computer took about 8 minutes to probable prime (PRP) test with Genefer OCL2.
Rod is a member of the Intel Corporation team.
The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 32GB RAM, running Debian Linux.
This computer took about 17 hours and 30 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 23 September 2019, 06:25:41 UTC, PrimeGrid's AP27 (Arithmetic Progression of 27 primes) Search found the first ever AP27:
224584605939537911+81292139*23#*n for n=0..26
In addition to being the first know AP27, it is also the largest known AP24, AP25 and AP26 (smaller start but larger end than old record).
The discovery was made by Rob Gahan ( Robish) of Ireland
using an NVIDIA GeForce GTX 1660 Ti GPU on an Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz running Microsoft Windows 10 Professional x64 Edition.
This computer took about 22 minutes to process this task.
Rob is a member of the Storm team.
For more information, please see the Official Announcement.
On 18 September 2019, 11:52:32 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2985036524288+1
The prime is 3,394,739 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 3 rd for Generalized Fermat primes and 28 th overall.
The discovery was made by Peter Harvey ( eXaPower) of the United States
using an NVIDIA GeForce GTX 1070 in an Intel(R) Core(TM) i5-4440S CPU @ 2.80GHz CPU with 8GB RAM, running Windows 8.1.
This computer took about 1 hour and 49 minutes to probable prime (PRP) test with GeneferOCL3.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Windows 10 Professional.
This computer took about 23 hours and 48 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 9 September 2019, 18:15:29 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
8521794262144+1
The prime is 1,816,798 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 13 th for Generalized Fermat primes and 76 th overall.
The discovery was made by Ken Ito ( jpldcon4) of Japan
using an NVIDIA GeForce GTX 980 Ti in an Intel(R) Xeon(R) CPU E5-2687W v3 @ 3.10GHz with 64GB RAM, running Microsoft Windows Server 2016.
This computer took about 27 minutes to probable prime (PRP) test with GeneferOCL2.
Ken is a member of Team 2ch.
The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 32GB RAM, running Debian Linux.
This computer took about 17 hours and30 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 2 September 2019, 03:39:59 UTC, PrimeGrid's Generalized Cullen/Woodall Prime Search found the largest known Generalized Cullen prime:
2805222·252805222+1
The prime is 3,921,539 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 1 st for Generalized Cullen primes and 21 st overall.
The discovery was made by Tom Greer of the United States
using an Intel(R) Core(TM) i9-9900X CPU @ 3.50GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition.
This computer took about 3 hours and 23 minutes to complete the primality test using multithreaded LLR.
Tom is a member of the Sicituradastra team.
For more information, please see the Official Announcement.
Other significant primes
|
News 
GFN-524288 Mega Prime!
On 24 December 2019, 08:20:15 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:
3214654^524288+1
The prime is 3,411,613 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 30th overall.
The discovery was made by Alen Kecic (Freezing)of Germany using a GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This GPU took about 51 minutes to complete the probable prime (PRP) test using GeneferOCL5. Alen is a member of the SETI.Germany Team.
The PRP was verified on 24 December 2019, 10:12:18 UTC by John Holmes (John J. Holmes) of the United States using a GeForce GTX 970 in an Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 hours, 4 minutes to complete the probable prime (PRP) test using GeneferOCL3.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 32GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 1 day, 1 hour, 45 minutes to complete the primality test using multithreaded LLR.
For more details, please see the official announcement.
13 Jan 2020 | 16:29:44 UTC
· Comment
ESP Mega Prime!
On 24 December 2019, 01:28:13 UTC, PrimeGrid's Extended Sierpinski Problem found the Mega Prime:
99739*2^14019102+1
The prime is 4,220,176 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 20th overall. This find eliminates k=99739; 9 k's remain in the Extended Sierpinski Problem.
The discovery was made by Brian D. Niegocki (Penguin) of the United States using an Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz with 1GB RAM, running Linux Ubuntu. This computer took about 14 hours, 14 minutes to complete the primality test using LLR. Brian is a member of the Antarctic Crunchers team.
The prime was verified on 24 December 2019, 04:37:31 UTC by Pavel Atnashev (Pavel Atnashev) of Russia using an Intel(R) Xeon(R) E5-2680 v2 @ 2.80GHz with 8GB RAM, running Linux. This computer took about 4 hours, 6 minutes to complete the primality test using LLR. Pavel is a member of the Ural Federal University team.
For more details, please see the official announcement.
13 Jan 2020 | 12:50:37 UTC
· Comment
And Another GFN-262144 Find!!
On 5 December 2019, 08:39:29 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:
9125820^262144+1
The prime is 1,824,594 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th for Generalized Fermat primes and 82nd overall.
The discovery was made by Yoshimitsu Kato (yoshi) of Japan using a GeForce GTX 1660 Ti in an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10. This GPU took about 22 minutes to complete the probable prime (PRP) test using Genefer OCL2. Yoshimitsu Kato is a member of Team JPN.
The prime was verified on 5 December 2019, 08:41:59 UTC by Igor Keller (IKI) of France using a GeForce GTX 1080 in an Intel(R) Core(TM) i5-4460 CPU @ 3.20GHz with 16GB RAM, running Microsoft Windows 8.1. This GPU took about 26 minutes to complete the probable prime (PRP) test using Genefer OCL2. Igor Keller is a member of the Gridcoin team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 16 hours, 30 minutes to complete the primality test using multithreaded LLR.
For more details, please see the official announcement.
24 Dec 2019 | 16:36:57 UTC
· Comment
GFN-262144 Find!
On 6 November 2019, 11:59:08 UTC, PrimeGrid's Generalized Fermat Prime Search found the Mega Prime:
8883864^262144+1
The prime is 1,821,535 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 14th for Generalized Fermat primes and 80th overall.
The discovery was made by Rod Skinner (rjs5) of the United States using a GeForce RTX 2080 Ti in an Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz with 63GB RAM, running Linux Fedora. This GPU took about 8 minutes to complete the probable prime (PRP) test using Genefer OCL2. Rod Skinner is a member of Intel Corporation team.
The prime was verified on 6 November 2019, 14:33:32 UTC by Tom Greer (tng*) of the United States using a GeForce RTX 2070 SUPER in an Intel(R) Core(TM) i9-9900X CPU @ 3.50GHz with 32GB RAM, running Microsoft Windows 10. This GPU took about 13 minutes to complete the probable prime (PRP) test using Genefer OCL2. Tom Greer is a member of the Sicituradastra. team.
The PRP was confirmed prime by an Intel(R) Xeon(R) E3-1240 v6 CPU @ 3.70GHz with 32 GB RAM, running Debian Linux. This computer took about 17 hours 30 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
24 Dec 2019 | 16:21:30 UTC
· Comment
First Ever AP27 Discovered!
The search is over!
After a three year effort, the first ever AP27 (Arithmetic Progression of 27 primes) has been found:
224584605939537911+81292139*23#*n for n=0..26
The AP27 was found by Rob Gahan (Robish) of Ireland. The discovery was made on an NVIDIA GeForce GTX 1660 Ti GPU on an Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz running Microsoft Windows 10 Professional x64 Edition. It took about 22 minutes and 34 seconds to process the task. Rob is a member of the Storm team.
Congratulations to everyone who participated in the AP27 search! It has been a very challenging and rewarding project.
For more information, please see the official announcement or our AP27 forums.
30 Sep 2019 | 20:41:09 UTC
· Comment
... more
News is available as an RSS feed 
Newly reported primes(Mega-primes are in bold.)
3591*2^1554003+1 (Darryl); 154427752^32768+1 (Walleye24); 4856365372257*2^1290000-1 (A1ex01); 7649*2^1553995+1 (Homefarm); 4857991827297*2^1290000-1 (Krzysiak_PL_GDA); 2435*2^3326969+1 (Randall J. Scalise); 4857905919975*2^1290000-1 (Honza); 154283086^32768+1 (SEARCHER); 4663*2^1553932+1 (Anthony Ayiomamitis); 9921*2^1553952+1 (composite); 154226532^32768+1 (Johny); 1749*2^1553890+1 (Homefarm); 595*2^2833406+1 (spnorton); 3959*2^1553833+1 (Anthony Ayiomamitis); 154114000^32768+1 (SEARCHER); 4852191577917*2^1290000-1 (bparsonnet); 4851101962005*2^1290000-1 (Honza); 154013032^32768+1 (Johny); 153972200^32768+1 (Johny); 71830642^65536+1 (SlangNRox) Top Crunchers:Top participants by RAC | Top teams by RAC |
| 
