A308413 Numbers k such that 23^(k+19) + 19^(k+17) + 17^(k+13) + 13^(k+11) + 11^(k+7) + 7^(k+5) + 5^(k+3) + 3^(k+2) - 1 is prime.

6, 60, 66, 414, 29340

Offset

1,1

Comments

a(6) > 50000 (if it exists).

Links

Table of n, a(n) for n=1..5.

Mathematica

ParallelTable[If[PrimeQ[23^(n+19) + 19^(n+17) + 17^(n+13) + 13^(n+11) + 11^(n+7) + 7^(n+5) + 5^(n+3) + 3^(n+2) - 1], n, Nothing], {n, 30000}]

Crossrefs

Cf. A306573.

Sequence in context: A217399 A098185 A173904 * A204093 A136927 A335202

Adjacent sequences: A308410 A308411 A308412 * A308414 A308415 A308416

Keyword

nonn,hard,more,less

Author

Mikk Heidemaa, May 31 2019

Status

approved