Author: Uri Blass
Date: 03:08:51 05/28/05
Go up one level in this thread
On May 28, 2005 at 05:24:51, Joseph Tadeusz wrote:
>On May 27, 2005 at 11:12:52, Vincent Diepeveen wrote:
>
>>A retry :
>>
>>// Diepeveen test to find mersenne primes
>>// test whether p is prime p = 2^n - 1
>>// when given n is prime
>>
>>t = 3;
>>for( j = 1 ; j < n ; j++ )
>> t = t*t; // mod p
>> if( t == p-3 ) printf("prime\n"); else printf("composite\n");
>>
>>3
>>9
>>19
>>20
>>28 <==> p-3 = 31 - 3 = 28
>>
>>Vincent
>
>Does this also work for primes larger than 31?
I do not know if it works for all of them.
It works for 127
1)t=3
2)t=9
3)t=81
4)t=6561 mod 127=84
5)t=7056 mod 127=71
6)t=5041 mod 127=88
7)t=7744 mod 127=124
124=127-3
127 is prime.
Uri
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