A139060 Primes of the form (4+k!)/4.

7, 31, 181, 1556755201, 12772735542927360001, 3877802510832746496000001, 65782709233423382541804503040000001, 203978820811974433586402817399028973568000000001

Offset

1,1

Comments

Numbers k for which (4+k!)/4 is prime see A139061

Links

Table of n, a(n) for n=1..8.

Mathematica

a = {}; Do[If[PrimeQ[(n! + 4)/4], AppendTo[a, (n! + 4)/4]], {n, 1, 50}]; a
Select[(4+Range[100]!)/4, PrimeQ] (* Harvey P. Dale, Oct 05 2016 *)

Prog

(PARI) for(k=4, 1e3, if(ispseudoprime(t=k!/4+1), print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011

Crossrefs

Cf. A082672, A089085, A089130, A117141, A007749, A139056, A139057, A139058, A139059, A139060, A139061, A139061, A139062, A139063, A139064, A139065, A139066, A020458.

Sequence in context: A172634 A322205 A139151 * A324621 A223144 A155521

Adjacent sequences: A139057 A139058 A139059 * A139061 A139062 A139063

Keyword

nonn

Author

Artur Jasinski, Apr 07 2008

Status

approved