From: recoder on 3 May 2010 08:27 Dear All, Sometimes I see this expression: Let Mq=u*v = (2aq+1)(2bq+1) where u and v are primes and Mq a mersenne number. This is true if there are only 2 prime factors of Mq. If we have more than 2 factors then (2bq+1) is not a prime but a product of primes. then (2bq+1)= (2cq+1) (2dq+1) (2eq+1) (2fq+1) .... Is there a way to detect if Mq has only 2 factors without trial factoring ? In addition, Is there a known rule for (2bq+1) as (2bq+1)= (2cq+1) (2dq+1) (2eq+1) (2fq+1) .... is not a prime and all the prime divisors are congruent to +- 1 mod 8.
From: Pubkeybreaker on 3 May 2010 10:06 On May 3, 8:27 am, recoder <kurtulmeh...(a)gmail.com> wrote: > Dear All, > Sometimes I see this expression: > Let Mq=u*v = (2aq+1)(2bq+1) where u and v are primes and Mq a mersenne > number. > This is true if there are only 2 prime factors of Mq. > If we have more than 2 factors then (2bq+1) is not a prime but a > product of primes. then (2bq+1)= (2cq+1) (2dq+1) (2eq+1) (2fq+1) .... > > Is there a way to detect if Mq has only 2 factors without trial > factoring ? > > In addition, > Is there a known rule for (2bq+1) as > (2bq+1)= (2cq+1) (2dq+1) (2eq+1) (2fq+1) .... is not a prime and all > the prime divisors are congruent to +- 1 mod 8. You already asked this in the Mersenne Forum. It has already been answered.
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