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Finding World Record Primes Since 1996


GIMPS newsletter #19, 2 December, 2003

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To: Great Internet Mersenne Prime Search (GIMPS) Registered Recipient

The Mersenne Newsletter, issue #19 December 2, 2003


1. GIMPS finds the 40th Mersenne Prime!!!
2. Welcome
3. Faster version 23 now available!
4. GIMPS Volunteers Create a Mersenne Forum
5. Progress since last newsletter

1. GIMPS finds the 40th Mersenne Prime!!!

On November 17th GIMPS member Michael Shafer at Michigan State
University proved 2^20996011-1 prime. At over 6.3 million digits it is
easily the largest known prime number, beating GIMPS' 2 year old
record of just over 4 million digits. You can read more about the
discovery at the GIMPS Home page,

Congratulations to Michael and all GIMPS members for our sixth success!
Good luck to all in the search for the 41st Mersenne prime! With a lot
of luck you could even share in the $100,000 EFF award for finding a
10,000,000 digit prime!!

2. Welcome

It has been over 2 years since the last newsletter. Welcome to
all the new GIMPS members that have joined since that time.

3. Faster version 23 now available

Version 23 is now available and it is up to 25% faster for Pentium 4 CPUs.
Athlon, Pentium III, and Celeron 2 processors will also get a modest speed

You can get the new version at
You'll find a complete list of version 23's new features at

To upgrade, stop and exit the current version. Optionally
make a backup of the directory. Install the new version on top of the
old version. Start the new version of the program.

You can upgrade immediately without waiting for your current work to complete.

4. GIMPS Volunteers Create a Mersenne Forum

Visit to communicate with your fellow
Mersenne Prime hunters. It is an excellent resource for solving
problems, learning about new developments, or just "hanging out".

5. Progress since last newsletter

While it doesn't seem like a lot is accomplished each day, it sure adds up.
In the last two years, we have reached the following milestones:

* 40th known Mersenne prime found M(20996011).
* 39th known Mersenne prime found M(13466917).
(a glitch prevented us from sending a newsletter)
* Double-checking proves M(6972593) is the 38th Mersenne prime.
* Over 120,000 exponents eliminated by finding a factor.
* Over 80,000 double-checks completed.
* Over 80,000 exponents tested for the first time!

You can watch the hourly progress of the search on the server's
status page at
and weekly status at


My thanks go to all GIMPS participants for contributing their spare CPU
cycles. During the last 8 years, we've accomplished more Mersenne prime
research than I ever could have imagined! Keep up the good work.
Hopefully, we'll find the 41st known Mersenne prime soon!!


George Woltman
woltman @


Scott Kurowski
primenet @


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