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February 2005: New Mersenne Prime!!
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42nd Known Mersenne Prime Found!

On February 18, 2005, Dr. Martin Nowak from Germany, found the new largest known prime number, 225,964,951-1. The prime number has 7,816,230 digits! It took more than 50 days of calculations on Dr. Nowak's 2.4 GHz Pentium 4 computer. The new prime was independently verified in 5 days by Tony Reix of Grenoble, France using a 16 Itanium CPU Bull NovaScale 5000 HPC running the Glucas program by Guillermo Ballester Valor of Granada, Spain. A second verification was completed by Jeff Gilchrist of Elytra Enterprises Inc. in Ottawa, Canada using 15 days of time on 12 CPUs of a Compaq Alpha GS160 1.2 GHz CPU server at SHARCNET.

Dr. Martin Nowak, an eye surgeon in Michelfeld, Germany learned of GIMPS in April 1999 when he read an article in his newspaper, the "Frankfurter Allgemeine Zeitung". Dr. Nowak, a math hobbyist, started with one PC and as his practice grew so did his participation in GIMPS. Six years later, he has 24 computers doing calculations for GIMPS -- and one Mersenne Prime to his credit!

Perfectly Scientific, Dr. Crandall's company which developed the FFT algorithm used by GIMPS, makes a poster you can order containing the entire number. It is kind of pricey because accurately printing an over-sized poster in 1-point font is not easy! Makes a cool present for the serious math nut in your family.

Dr. Nowak could not have made this discovery alone. In recognition of contributions made by tens of thousands GIMPS volunteers, credit for this new discovery will go to "Nowak, Woltman, Kurowski, et al". The discovery is the eighth record prime for the GIMPS project. Join now and you could find the next record-breaking prime! You could even win some cash.

For more information on this latest prime discovery read the full press release.

M971 factored

On September 13, 2004 David Symcox found a 53-digit factor for M971. This was the smallest Mersenne number for which no factors were known! Visit this page for information on how your computer can help factor these small Mersenne numbers.

41st Known Mersenne Prime Found!!

On May 15, 2004, Josh Findley discovered the 41st known Mersenne Prime, 224,036,583-1. The number is nearly a million digits larger than our last find and is now the largest known prime number!

Congratulations to Josh and every GIMPS contributor for their part in this remarkable find. You can download the client for your chance at finding the next world record prime! A forum for newcomers is available to answer any questions you may have.

Josh's calculation took just over two weeks on his 2.4 GHz Pentium 4 computer. Josh has been a GIMPS participant for 5 years, proving the value of having great patience. The new prime was verified by Tony Reix in just 5 days using only half the power of a Bull NovaScale 5000 HPC running Linux on 16 Itanium II 1.3 GHz CPUs. A second verification was completed by Jeff Gilchrist of Elytra Enterprises Inc. in Ottawa, Canada using eleven days of time on a HP rx5670 quad Itanium II 1.5 GHz CPU server at SHARCNET. Both verifications used Guillermo Ballester Valor's Glucas program.

If you want to see the number in written in decimal and don't mind downloading a large file, you can see the full 7,235,733 decimal digits.

For more information, the press release is available.

NFSNet / Cunningham project needs your help!!

The Cunningham project is trying to complete the factorization of 2^n-1 and 2^n+1 where n < 1200. To do this they need to find as many "small" factors as possible using ECM. Computers of all speeds are welcome, but this project is ideal for slower computers because primality tests on large Mersenne numbers can take months to complete. Visit 2^n-1 and 2^n+1 for current ECM status. Visit the forums for help setting up prime95 to run ECM curves. Note for performance reasons Pentium 4 computers should only test 2^n-1 numbers.

Other Recent News

Version 23 is available. P4 users will find it up to 25% faster than version 22. Athlon and Pentium 3 users get a small speed increase too.

M6972593 is the 38th Mersenne prime. GIMPS has finished testing and double-checking all Mersenne numbers below M6972593. This proves there are no smaller undiscovered Mersenne primes.

GIMPS forums. Here you can chat with fellow GIMPS members, get help with installation questions, learn more about how GIMPS works, etc.

Make Math History!!

You could discover one of the most coveted finds in all of Mathematics - a new Mersenne prime number. We've found seven already. Join in on this fun, yet serious research project. All you need is a personal computer, patience, and a lot of luck.

In addition to the joy of making a mathematical discovery, you might win some cash. The Electronic Frontier Foundation is offering a $100,000 award to the first person or group to discover a ten million digit prime number! See how GIMPS will distribute this award if we are lucky enough to find the winning ten million digit prime.

What are Mersenne primes and why do we search for them?

Prime numbers have long fascinated amateur and professional mathematicians. An integer greater than one is called a prime number if its only divisors are one and itself. The first prime numbers are 2, 3, 5, 7, 11, etc. For example, the number 10 is not prime because it is divisible by 2 and 5. A Mersenne prime is a prime of the form 2P-1. The first Mersenne primes are 3, 7, 31, 127, etc. There are only 41 known Mersenne primes.

GIMPS, the Great Internet Mersenne Prime Search, was formed in January 1996 to discover new world-record-size Mersenne primes. GIMPS harnesses the power of thousands of small computers like yours to search for these "needles in a haystack".

Most GIMPS members join the search for the thrill of possibly discovering a record-setting, rare, and historic new Mersenne prime. Of course, there are many other reasons.

Site Map

The How it Works page tells you what hardware you need and how the program runs.
The Download page lets you download the free software.
The FAQ page answers some frequently asked questions.
The benchmarks page compares the programs speed on many different CPU types.
The Prizes page tells you how GIMPS will divide any prize money.
The Status page tells you how the search is progressing.
The Top Producers page ranks participants by CPU time contributed.
The PrimeNet page gives statistics maintained by the server.
The History page gives a brief history of the project.
The Math page describes the math and algorithms GIMPS uses.
The Source code page lets you download the source code and gives UNIX users a pointer to code they can use.
The Mailing list page lets you subscribe to a mailing list that discusses Mersenne numbers.
The Manual testing page lets you pick exponents to test if you cannot get the PrimeNet server to work.
The Credits page lists many of the people that have helped GIMPS over the years.
The Links page gives you pointers to several other web sites.
The Other projects page gives you pointers to other distributed computing projects.

Last updated: March 6, 2005
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