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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.
0
6, 60, 66, 414, 29340
OFFSET
1,1
COMMENTS
a(6) > 50000 (if it exists).
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
KEYWORD
nonn,hard,more,less
AUTHOR
Mikk Heidemaa, May 31 2019
STATUS
approved