A289757 Primes of the form k!7-1, where k!7 is the septuple factorial number (A114799).

2, 3, 5, 7, 17, 29, 43, 59, 97, 509, 1559, 12239, 198719, 379439, 633599, 1136678399, 33739804799, 99298742399, 1990648483199, 59126328543388935628799, 3797826416991538753535999, 2409161546475779555007420356689919999, 9325555101161759039183007326207999999

Offset: 1

Author

Robert Price, Jul 11 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..34
• Henri & Renaud Lifchitz, PRP Records.Search for n!7-1.
• Joe McLean, Interesting Sources of Probable Primes
• OpenPFGW Project, Primality Tester

Crossrefs

Cf. A156167.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 7] - 1, {i, 2, 100}], PrimeQ[#]&]