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Topic: Newly Discovered Titanic Prime
Replies: 20   Last Post: Oct 8, 2001 11:45 AM

 Messages: [ Previous | Next ]
 Phil Carmody Posts: 62 Registered: 12/13/04
Re: Newly Discovered Titanic Prime
Posted: Oct 8, 2001 11:45 AM

Denis Feldmann wrote:
> > That number is not prime.
>
> Why are you so confident?
>

> >
> > I used ProvablePrimeQ on the number and it returned False.

>
> Maple answers isprime (10*((10^1139-1)/9)+9+9*10^1140) by "true" after 1 mn
> 30 on my PC. Admittedly, this is only probabilistic testing, but no
> counterexample has ever been found for isprime
> (from the Maple "help" file :
> "The function isprime is a probabilistic primality testing routine.
> It returns false if n is shown to be composite within one strong
> pseudo-primality test and one Lucas test and returns true otherwise. If
> isprime returns true, n is ``very probably'' prime - see Knuth ``The art of
> computer programming'', Vol 2, 2nd edition, Section 4.5.4, Algorithm P for a
> reference and H. Reisel, ``Prime numbers and computer methods for
> factorization''. No counter example is known and it has been conjectured
> that such a counter example must be hundreds of digits long." )

should take only an hour or so, as it's a small number.
http://primepages.org/ has a links section which will point to it, or a
google search for it. It is the current ECPP world record holder, and
runs on most x86 windows platforms, and also under Wine on x86
Linux/*BSD.

Phil

Date Subject Author
9/27/01 Richard Carr
9/27/01 Richard Carr
10/6/01 ddtouie
10/6/01 ddtouie
10/6/01 Michael Varney
10/6/01 ddtouie
10/7/01 Michael Varney
10/7/01 Denis Feldmann
10/7/01 Michael Varney
10/7/01 Jerry Walker
10/7/01 Michael Varney
10/8/01 Jerry Walker
10/8/01 Michael Varney
10/8/01 Richard Carr
10/7/01 Dave Seaman
10/8/01 Phil Carmody
10/7/01 ignacio.larrosa@eresmas.net
10/7/01 Jerry Walker
10/7/01 Richard Carr
9/27/01 Matthias Mahnke
9/27/01 The Scarlet Manuka