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-   -   Factor me this (https://www.mersenneforum.org/showthread.php?t=4514)

penguinman007 2005-08-18 09:49

Factor me this
 
e.g Can someone tell me if the following number is prime (or how do I find out for myself):

(2 ^ 65536) + 1


Penguinman007

jinydu 2005-08-18 10:58

This question was already posted in the Soap Opera

akruppa 2005-08-18 16:00

...but better fits into the Factoring forum.
This is the 16-th Fermat number. The small Fermat numbers have received great factoring efforts already, discovering new factors will be very hard. Use Google or the Forum search to find out more.

Alex

sean 2005-08-18 20:33

No it is not prime. We can tell you this without exhibiting a factor.

ATH 2005-08-21 11:19

[URL=Fermat factoring status]http://www.prothsearch.net/fermat.html[/URL]

As you can se under F16 there is 2 known factors 825753601 and 188981757975021318420037633 but there is still a 19694 digit number left that is composite.


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