A172997 Numbers n such that for p=prime(n), (2p-1)^(2p-1) mod 2^(2p-1) is prime.
1, 5, 6, 8, 34, 131
Offset: 1
Keywords
Examples
5 is in the sequence, since prime(5)=11 and (2*11-1)^(2*11-1) mod 2^(2*11-1) = 21^21 mod 2^21 = 1472837 is prime.