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## Re: factor and large prime numbers

**From**: |
Sami Kerola |

**Subject**: |
Re: factor and large prime numbers |

**Date**: |
Mon, 22 Jul 2013 16:09:11 +0100 |

On 22 July 2013 16:01, Sami Kerola <address@hidden> wrote:
>* I were curious how quickly factor will process prime numbers, and*
>* found something rather strange. For example these five can be computed*
>* quite quickly.*
>
>* time factor 10333147966386144929666651337523199999999*
>* time factor 371993326789901217467999448150835199999999*
>* time factor 13763753091226345046315979581580902399999999*
>* time factor 523022617466601111760007224100074291199999999*
>* time factor 20397882081197443358640281739902897356799999999*
Opps. A silly mistake. Not only one of the above is prime.
time factor 523022617466601111760007224100074291199999999
But that hardly changes the strangeness...
>* But much smaller numbers will take ages to give results (to be honest*
>* I gave up).*
>
>* time factor 8683317618811886495518194401279999999*
>* time factor 295232799039604140847618609643519999999*
>
>* Any idea what is going on?*
...smaller primes can be a lot slower to factor than greater.
--
Sami Kerola
http://www.iki.fi/kerolasa/