# Fun_People Archive 30 SepWhiteBoardness - 9/29/97

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From: Peter Langston <psl>
Date: Tue, 30 Sep 97 14:50:50 -0700
To: Fun_People
Subject: WhiteBoardness - 9/29/97

Forwarded-by: Joseph Harper <joeha@MICROSOFT.com>
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Hampshire, England:

If it were written out, it would stretch for 1.4 miles.  If it were read
out, it would take 224 hours. The world's largest known Mersenne prime
number -- containing 895,932 digits -- has been discovered by an information
technologist from Hampshire, England.

A prime number is divisible only by itself and one.  Three is a prime
number, and so are 5, 7 and 11.

The number discovered by Gordon Spence, 38, is so long that it would fill
a 450-page paperback book. To recite it would take a month of eight-hour
days.

Fortunately, it is written in the relatively terse notation of the 17th
century French monk Marin Mersenne, which takes the form of 2 multiplied by
an exponent, minus 1. The exponent is 2,976,221. This means that 2 is
multiplied by itself 2,976,221 times and then one is subtracted. Until now,
only 35 Mersenne primes have ever been found.

Prime numbers are one of the tools of encryption. But prime numbers of that
magnitude are almost sublimely useless.

Spence, who announced his discovery on the Internet, got involved in the
Great Internet Mersenne Prime Search as one of 2,000 volunteers using a
program written by George Woltman, a 39-year-old Florida computer
programmer. He said: "I was just lucky to get the right range of numbers to
check."

It took his computer 15 days to complete the calculation to show that his
number was indeed divisible only by itself and one. He then had to ask
someone with a Cray T90 supercomputer to check the answer.

He said: "I saw it as my only real opportunity to make a little mark on
history. It was several thousands to one against. There are only 36 known
to exist."
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Montecantini, Italy:

An Italian porn star who signed a sponsorship deal with the Lazio Rugby club
has agreed to another joint venture, this time with a women's soccer team.

Jessica Rizzo, one of Italy's better-known porn actresses, said Thursday
she would sponsor a team from the town of Montecatini in Tuscany.

Both Lazio and Montecatini will have Rizzo's name emblazoned across their
shirts when their league seasons begin next month.

Rizzo owns a satellite television channel that broadcasts hard-core
pornography. The shirts will promote the decoder cards needed to access the
channel.
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