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Old 2005-12-29, 08:58   #4
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Jun 2003

115518 Posts

Originally Posted by jasong
I've heard(possibly incorrectly) that it is conjectured that if one form(k*2^n-1) is found prime, than the other form(n*2^k-1) also has a prime, and vice-versa.
Can you clarify this? when you say "the other form(n*2^k-1) also has a prime", do you mean n*2^k-1 _is_ prime or n*2^<some k> -1 is prime?

At any rate, I highly doubt it if the conjucture is true! All you have to do is find a prime of the form x*2^509203-1 for some x. By the conjucture, you will expect to have a prime 509203*2^x-1. Unfortunately, since 509203 is a Riesel number, there won't be any such primes.

Am I getting close?

Last fiddled with by axn on 2005-12-29 at 08:58
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