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Old 2005-01-15, 19:19   #1
VJS
 
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Default How do I prove a 4000 digit number is prime??

I have one 31-digit factor from a number of the k*2^n+1 type where n=~7300,

How do I check if the "Co-factor" is prime, it ends in ....1162049124129

Thanks
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Old 2005-01-15, 19:40   #2
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Not to get everyone excited I don't think the co-factor is prime, but how do I check or continue to find factors of this "co-factor"...
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Old 2005-01-15, 20:30   #3
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I'll try

http://www.alpertron.com.ar/ECM.HTM

You can put use raw interger numbers... in addition to equations.

It will do a Rabin probabilistic prime check
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Old 2005-01-15, 21:35   #4
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Lately, I've found Primo, which seems to be a relatively fast primalty proving program for numbers of no special form.
Unfortunately, 4000 digits will most likely still take several weeks or even months.

It seems like Jens Franke et. al have a distributed primalty proving program, though.
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Old 2005-05-09, 20:56   #5
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Quote:
Originally Posted by Mystwalker
Lately, I've found Primo, which seems to be a relatively fast primalty proving program for numbers of no special form.
Unfortunately, 4000 digits will most likely still take several weeks or even months.

It seems like Jens Franke et. al have a distributed primalty proving program, though.
I went to the website and discovered some comments about the US, Canadian, and Japanese patent laws being so overly patent-happy(my word) that the writer fears getting sued. The thing is, even though he says the usage is forbidden the download proceeds without a hitch.

Am I breaking any laws if I use this software?

Edit: I'm a US resident in Arkansas.

Last fiddled with by jasong on 2005-05-09 at 20:57
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