%N Greater of twin primes p such that 2^p-1 is prime.
%C Also 74207281 is a member, but its position is not known yet.
%o (PARI) is(n) = isprime(n)&&isprime(n-2)&&ispseudoprime(2^n-1)
%Y Intersection of A000043 and A006512.
%Y Cf. A087858.
%A _Jeppe Stig Nielsen_, Jan 03 2018