Mersenne: Re: Factor of 2^(2^31-1)-1 found ($

1999-09-19 Thread Lucas Wiman

Oopsy.  That should have read J. L. Selfridge

-lucas
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Mersenne: Re: Factor of 2^(2^31-1)-1 found ($)

1999-09-19 Thread Chris Nash

Hi Lucas

 Yesterday (and the day before), I went to the Illinois number theory
conference.
 There (2nd talk of yesterday) J. P. Selfridge announced that he would
 give away $1000 US for any factor found of a number which ought to be
 prime (he provided a list).  On that list was 2^(2^31-1)-1.
 To guard against errors in transmitions the factor is 295257526626031

p=295257526626031
I took 2, and squared it 31 times mod p. And got the result

2^(2^31)=2 mod p

Congratulations Lucas, it is indeed a factor of 2^(2^31-1)-1 well done!
Had it already been shown that M(M(p)) is not necessarily prime?

Chris Nash
Lexington KY
UNITED STATES


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