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Old 2006-09-11, 01:49   #2
dsouza123
 
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Sep 2002

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What program are you running ?

When you wrote Fermat factoring do you mean factoring Fermat numbers ?

If so, then they are numbers such as F5, the fifth Fermat number,
F1 through F4 are prime.

Fermat numbers take the form of 2^2^n + 1
and the factors are of the form k*2^(n+2) + 1.

For example F5 means
2^2^5 + 1 = 2^32 + 1 = 4294967296 + 1 = 4294967297.
and potential factors are k*2^(5+2) + 1 = k*2^7 + 1 = k*128 + 1
with k taking the values 1 through 33554432, 33554432 = 2^25 = 2^(32-7).

It has been factored, of which two factors are
5*2^7 + 1 = 5*128 + 1 = 641
52347*2^7 + 1 = 52347*128 + 1 = 6700416 + 1 = 6700417
641 * 6700417 = 4294967297.
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