A151892 Numbers m such that m! + (next prime after m!) is prime.

1, 2, 3, 4, 6, 7, 14, 15, 20, 25, 32, 34, 35, 67, 89, 191, 316, 411, 1213, 1280, 2022, 2267

Offset: 1

Author

Artur Jasinski, Apr 12 2008

Keywords

• nonn
• more
• hard

Crossrefs

Cf. A002981, A151894, A151893, A151903, A084749.

Programs

Mathematica

a = {}; Do[If[PrimeQ[n! + NextPrime[n! ]], AppendTo[a, n]], {n, 200}]; a (* Artur Jasinski *)
Select[Range[420],PrimeQ[#!+NextPrime[#!]]&] (* Harvey P. Dale, Aug 20 2021 *)

Extensions

a(17)-a(18) from Robert G. Wilson v, Jun 11 2010

a(19)-a(20) from Michael S. Branicky, May 27 2023

a(21)-a(22) from Michael S. Branicky, Aug 03 2024