A297674 Greater of twin primes p such that 2^p-1 is prime.

5, 7, 13, 19, 31, 61, 1279, 4423, 110503, 132049, 20996011, 24036583

Offset

1,1

Comments

Also 74207281 is a member, but its position is not known yet.

Links

Table of n, a(n) for n=1..12.

Mathematica

twinPrimeBelowQ[n_]:=PrimeQ[n-2]
Table[MersennePrimeExponent[n], {n, 47}] // Select[twinPrimeBelowQ]
(* David R. Kirkby, Jul 19 2021 *)

Prog

(PARI) is(n) = isprime(n)&&isprime(n-2)&&ispseudoprime(2^n-1)

Crossrefs

Intersection of A000043 and A006512.

Cf. A087858.

Sequence in context: A074304 A264865 A293712 * A072677 A117249 A063910

Adjacent sequences: A297671 A297672 A297673 * A297675 A297676 A297677

Keyword

nonn,hard,more

Author

Jeppe Stig Nielsen, Jan 03 2018

Status

approved