A288717 Primes of the form k!7+1, where k!7 is the septuple factorial number (A114799).

2, 3, 5, 7, 19, 31, 61, 79, 12241, 19801, 29641, 76561, 379441, 2016841, 2756161, 1838865601, 4150656721, 337767408001, 956960801281, 21617114112001, 1534815101952001, 9590944392057601, 30891838760640001, 119715577952256001, 767275551364608001

Offset: 1

Author

Robert Price, Jun 13 2017

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..46
• Henri& Renaud Lifchitz, PRP Records.Search for n!7+1.
• Joe McLean, Interesting Sources of Probable Primes
• OpenPFGW Project, Primality Tester

Crossrefs

Cf. A156165.

Programs

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 7] + 1, {i, 0, 100}], PrimeQ[#]&]
Select[Table[Times@@Range[n,1,-7]+1,{n,100}],PrimeQ] (* Harvey P. Dale, Dec 23 2022 *)