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Finding World Record Primes Since 1996


GIMPS newsletter #3, 12 April, 1996

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The Mersenne Newsletter, issue #3 April 12, 1996


Since the last newsletter 45 days ago, we've added 35 new members to
our ranks. This brings to more than 75 people and 90 computers
involved in the search. Welcome to all the new searchers!


Also over the past 45 days, we've proven 1,389 Mersenne numbers
composite. This leaves us with "only" 25,608 untested Mersenne
numbers with exponents below 1,300,000. If you use a 90 MHz Pentium
as a standard, these 25,608 numbers can be tested in just over
129 CPU years.

Keep those results rolling in! Someone is bound to find a Mersenne
prime sooner or later!

Program News

A new version of the program has been placed on the web. You can download
it from
I recommend everyone upgrade to this version at their earliest convenience.
Some highlights of the new version:

Thanks to Albert van der Horst and Richard Hibberd the program no
longer crashes in Windows 3.1!!! You can now work in other Windows
applications while prime.exe is running!

Rather than a simple test of 2^19937-1, the program will now perform
an hour long self-test of many different exponents. This should catch
any machine not capable of running Lucas-Lehmer tests.

You can now get a status report on your range. Choose Range
Status from the menus to get a report on the number of Mersenne
numbers left to test, expected time to completion, etc. This
information is also displayed whenever you choose a new range
with Range Start or Range Next.

Factoring speed has been doubled for Pentiums. 486 machines will
notice a 15% improvement when factoring.

As always, comments and suggestions for future enhancements are welcome.

Happy hunting,
George Woltman