
919444^1048576+1 (new Generalized Fermat mega prime) - seycombi
https://www.primegrid.com/forum_thread.php?id=7597
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timonoko
Is this one of those primes that are all 1's in binary?

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gus_massa
No, but it's a relevant question anyway.

Mersenne prime: 2^n-1, for example 31=11111[base 2], we know 49 of them

Fermat prime: 2^(2^n)+1: for example 17=10001[base 2], we know 5 of them]

This is similar to a Fermat prime, but it's not exactly a Fermat prime. So the
binary representation is horrible.

The main idea is that is you know the prime factorization of N+1 or N-1, then
it's helpful to test if N is prime or not.

