A365063 Least k such that k*A000668(n)*A000668(n+2) + 1 is prime, where A000668(n) is the n-th Mersenne prime.

4, 4, 6, 34, 4, 18, 4, 10, 34, 60, 208, 442, 976, 1548, 1918, 1726, 3828, 210, 17940, 34254, 1852, 19986, 7728, 22186, 9966

Offset

1,1

Comments

If they exist, a(26) > 31373, a(27) > 419, a(28) > 87.

Links

Table of n, a(n) for n=1..25.

Mathematica

Table[k=1; Monitor[Parallelize[While[True, If[PrimeQ[k*(2^MersennePrimeExponent[n]-1)*(2^(MersennePrimeExponent[n+2])-1)+1], Break[]]; k++]; k], k], {n, 1, 25}]

Crossrefs

Cf. A000668 (Mersenne primes), A098917, A365064, A365065.

Sequence in context: A264578 A261146 A368304 * A090531 A350581 A356686

Adjacent sequences: A365060 A365061 A365062 * A365064 A365065 A365066

Keyword

nonn,more

Author

J.W.L. (Jan) Eerland, Aug 19 2023

Status

approved