[torbjorn]

Mersenne primes can be written as: 2^(some prime) - 1. Is there a name for the primes that can be written as: 2^(some prime) + 1?

[zamadatix]

Interestingly there are only 6 known primes of the form 2^n+1. Other than "2" these are all Fermat primes of the form 2^(2^n)+1 and so there is only a single known case n is prime - the case of n=2.

https://oeis.org/A092506 https://oeis.org/A019434