A289758 Primes of the form k!5-1, where k!5 is the quintuple factorial number (A085157).

2, 3, 5, 13, 23, 167, 311, 503, 1696463, 3616703, 119351231, 393749999, 388856692223, 35437499999999, 728640635326636031, 3885182313590882303, 19837740893195045044223, 5126863427472785697108393983, 140901732869280543971697196500573487103

Offset: 1

Author

Robert Price, Jul 11 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..27
• Henri & Renaud Lifchitz, PRP Records.Search for n!5-1.
• Joe McLean, Interesting Sources of Probable Primes
• OpenPFGW Project, Primality Tester

Crossrefs

Cf. A085149.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 5] - 1, {i, 2, 100}], PrimeQ[#]&]