# [ExI] prime

spike spike66 at att.net
Wed Feb 6 05:57:55 UTC 2013

```

...

A friend who knows how I am, and is my friend anyway, sent me this link:

http://arstechnica.com/science/2013/02/volunteer-discovers-a-new-17-million-
digit-prime-number/

in which is found the following comment:

"A Mersenne prime is a prime number that can be written in the form Mp =
2n-1, and they're extremely rare finds. Of all the numbers between 0 and
2^25,964,951-1 there are 1,622,441 that are prime, but only 42 are Mersenne
primes."

Oh boy, from the standpoint of orders of magnitude, this might be the
largest error in the history of publishing.  The number of primes between 0
and 25,964,951-1 is not 1,622,441.  It is a number on the order of 1E(seven
million) rather than on the order of 1E6.  So they missed it by more than 7
million orders of magnitude.  I know of no other error of that size.  That
error is unimaginably larger than estimating the mass of the visible
universe at less than the mass of an electron, if you measure it in the
number of orders of magnitude between the right answer and the given answer.

What they meant is there are 1,622,441 Mersenne numbers between 0 and
2^25964,951-1, a Mersenne number being defined as a number of the form 2^P-1
where p is prime.

But we will forgive.  Probably some prime virgin wrote the article.

I on the other hand, am just the opposite of a prime virgin.  I am a total
prime slut, a complete prime whore.  I will do anything for primes,
anything.

spike

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20130205/a83cfa3f/attachment.html>
```