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 20 June 2017, 17:28:20 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
953·23405729+1
The prime is 1,025,230 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 201 st overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4590 @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour and 14 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 13 June 2017, 10:46:25 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
833·23403765+1
The prime is 1,024,639 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 202 nd overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4590 @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour and 21 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 4 June 2017, 04:02:39 UTC, PrimeGrid's Generalized Fermat Prime Search project found the Generalized Fermat mega prime:
46413358131072+1
The prime is 1,004,883 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 23 rd for Generalized Fermat Primes and 235 th overall.
The discovery was made by Sagi Iltus ( sagiil)
using an Intel(R) Xeon(R) E5-2673 v3 CPU at 2.40GHz with 8GB RAM, running Linux.
This computer took about 7 hours and 4 minutes to complete the probable prime (PRP) test using Genefer.
For more information, please see the Official Announcement.
On 31 May 2017, 09:22:45 UTC, PrimeGrid's Generalized Fermat Prime Search project found the Generalized Fermat mega prime:
46385310131072+1
The prime is 1,004,848 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 23 rd for Generalized Fermat Primes and 235 th overall.
The discovery was made by Matt Jurach ( mattozan) of the United States
using an AMD Pitcairn GPU in an Intel(R) Core(TM) i7-5820K CPU at 3.30GHz with 16GB RAM, running Microsoft Windows 7 Enterprise Edition.
This computer took about 42 minutes to complete the probable prime (PRP) test using GeneferOCL2.
Matt is a member of the Aggie The Pew team.
For more information, please see the Official Announcement.
On 29 May 2017, 07:16:40 UTC, PrimeGrid's Generalized Fermat Prime Search project found the Generalized Fermat mega prime:
46371508131072+1
The prime is 1,004,831 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 23 rd for Generalized Fermat Primes and 235 th overall.
The discovery was made by Mike Kinney ( Mektacular) of the United States
using an NVIDIA GeForce GTX 950 in an Intel(R) Xeon(R) E5-2670 CPU at 2.60GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition.
This computer took about 21 minutes to complete the probable prime (PRP) test using GeneferOCL2.
Mike is a member of the Crunching@EVGA team.
For more information, please see the Official Announcement.
On 27 May 2017, 18:34:13 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
1167·23399748+1
The prime is 1,023,430 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 202 nd overall.
The discovery was made by Eric Eskam ( Doc No) of the United States
using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 8GB RAM, running Microsoft Windows 10 Professional Edition. This computer took about 1 hour and 17 minutes to complete the primality test using LLR.
Eric is a member of the Heinlein Fans team.
For more information, please see the Official Announcement.
Other significant primes
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News 
Another PPS-Mega Prime!
On 20 June 2017, 17:28:20 UTC, PrimeGrid’s PPS Mega Prime Search project found the Mega Prime:
953*2^3405729+1
The prime is 1,025,230 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 201st overall.
The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 14 minutes to complete the primality test using LLR.
The prime was verified on 24 June 2017 06:23:26 UTC, by Jon Goral ([KWSN]John Galt 007) of the United States using an Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz with 10GB RAM, running Microsoft Windows 10 Core Edition. This computer took about 5 hours 54 minutes to complete the primality test using LLR. Jon is a member of The Knights Who Say Ni! team.
For more details, please see the official announcement.
26 Jun 2017 | 12:24:58 UTC
· Comment
Finally, Another PPS-Mega Prime!
On 13 June 2017, 10:46:25 UTC, PrimeGrid’s PPS Mega Prime Search project found the Mega Prime:
833*2^3403765+1
The prime is 1,024,639 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 202nd overall.
The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 8GB RAM, running Linux. This computer took about 1 hour 21 minutes to complete the primality test using LLR.
The prime was verified on 13 June 2017, 16:05:06 UTC by Michael Bowe (No_Name) of Germany using an Intel(R) Xeon(R) E3-1230 v5 CPU @ 3.40GHz with 32GB RAM, running Microsoft Windows Server 2012 R2 Foundation Edition. This computer took about 1 hour 24 minutes to complete the primality test using LLR. Michael is a member of the SETI.Germany team.
For more details, please see the official announcement.
14 Jun 2017 | 12:50:32 UTC
· Comment
Yet Another GFN-131072 Mega Prime!
On 4 June 2017, 04:02:39 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
46413358^131072+1
The prime is 1,004,883 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.
The discovery was made by Sagi Iltus (sagiil) using an Intel(R) Xeon(R) E5-2673 v3 CPU at 2.40GHz with 8GB RAM, running Linux. This CPU took about 7 hours 4 minutes to probable prime (PRP) test with Genefer.
The prime was verified on 7 June 2017, 18:18:37 UTC by Dirk Broer (Dirk Broer) of the British Virgin Islands using an AMD Athlon(TM) 5350 APU with 16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 4 hours 1 minute to probable prime (PRP) test with GeneferOCL2. Dirk is a member of the AMD Users team.
The PRP was confirmed prime by an Intel(R) Xeon (R) E5-2670 CPU CPU @ 2.60GHz with 32GB RAM, running Linux. This computer took about 15 hours 21 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
7 Jun 2017 | 19:24:18 UTC
· Comment
Another GFN-131072 Mega Prime!
On 31 May 2017, 09:22:45 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
46385310^131072+1
The prime is 1,004,848 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.
The discovery was made by Matt Jurach (mattozan) of the United States using an AMD Pitcairn GPU in an Intel(R) Core(TM) i7-5820K CPU at 3.30GHz with 16GB RAM, running Microsoft Windows 7 Enterprise Edition. This GPU took about 42 minutes to probable prime (PRP) test with GeneferOCL2. Matt is a member of the Aggie The Pew team.
The prime was verified on 31 May 2017, 22:53:40 UTC by Krzysztof Ostaszewski (Krzysiak_PL_GDA) of Poland using an AMD R9 Fury Series GPU in an Intel(R) Xeon(R) E5-2683 v3 CPU at 2.00GHz with 32GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 11 minutes to probable prime (PRP) test with GeneferOCL2. Krzysztof is a member of the BOINC@Poland team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 52 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
1 Jun 2017 | 10:32:06 UTC
· Comment
GFN-131072 Mega Prime!
On 29 May 2017, 07:16:40 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
46371508^131072+1
The prime is 1,004,831 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 23rd for Generalized Fermat primes and 235th overall.
The discovery was made by Mike Kinney (Mektacular) of the United States using an NVIDIA GeForce GTX 950 in an Intel(R) Xeon(R) E5-2670 CPU at 2.60GHz with 64GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 21 minutes to probable prime (PRP) test with GeneferOCL2. Mike is a member of the Crunching@EVGA team.
The prime was verified on 29 May 2017, 14:11:46 UTC by Matt Jurach (mattozan) of the United States using an NVIDIA GeForce GTX 460 in an Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz with 8GB RAM, running Microsoft Windows 7 Ultimate Edition. This GPU took about 36 minutes to probable prime (PRP) test with GeneferOCL2. Matt is a member of the Aggie The Pew team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional. This computer took about 2 hours 41 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
30 May 2017 | 11:20:48 UTC
· Comment
... more
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Newly reported primes6451*2^1451648+1 (Honza1616); 54070422^32768+1 (DaveSun); 3577401625047*2^1290000-1 (Randall J. Scalise); 54049292^32768+1 (TimT); 54044372^32768+1 (TimT); 3577151936895*2^1290000-1 (Randall J. Scalise); 1707*2^1451599+1 (Randall J. Scalise); 54032224^32768+1 (TimT); 3566766963207*2^1290000-1 (pschoefer); 3574489599567*2^1290000-1 (ETX); 3575368535445*2^1290000-1 (gallarr); 3564763208937*2^1290000-1 (zunewantan); 3149*2^1451593+1 (Randall J. Scalise); 24528070^65536+1 (Skligmund); 3566251544487*2^1290000-1 (ruchstef); 3483*2^1451540+1 (Randall J. Scalise); 3572077639797*2^1290000-1 (vaughan); 24510980^65536+1 (Guan-Wei Chen); 3571328286825*2^1290000-1 (zunewantan); 3566794387557*2^1290000-1 (tng*) Last 24 hoursTop participants by work done in the last 24 hours | Top teams by work done in the last 24 hours |
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