A289756 Primes of the form k!8-1, where k!8 is the octuple factorial number (A114800).

2, 3, 5, 7, 19, 47, 83, 127, 359, 1847, 26879, 55439, 13366079, 188743679, 38761631999, 9033331507199, 3896394330931199, 152349556104345599, 5305528527460761599, 57299708096576225279999, 160680029832131217407999, 383414179456168545484799

Offset: 1

Author

Robert Price, Jul 11 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..30
• Henri & Renaud Lifchitz, PRP Records.Search for n!8-1.
• Joe McLean, Interesting Sources of Probable Primes
• OpenPFGW Project, Primality Tester

Crossrefs

Cf. A204662.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 8] - 1, {i, 2, 100}], PrimeQ[#]&]