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A297674 Greater of twin primes p such that 2^p-1 is prime. 2
5, 7, 13, 19, 31, 61, 1279, 4423, 110503, 132049, 20996011, 24036583 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Also 74207281 is a member, but its position is not known yet.
LINKS
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
KEYWORD
nonn,hard,more
AUTHOR
Jeppe Stig Nielsen, Jan 03 2018
STATUS
approved

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Last modified March 19 07:04 EDT 2024. Contains 370953 sequences. (Running on oeis4.)