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

1,1

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

Mathematica

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

Crossrefs

Cf. A156167.

Sequence in context: A356475 A178382 A360591 * A030480 A048418 A074788

Adjacent sequences: A289754 A289755 A289756 * A289758 A289759 A289760

Keyword

nonn

Author

Robert Price, Jul 11 2017

Status

approved