A139068 Primes of the form k!/9 + 1.

4481, 611402462201343216650033936533361654773516861440000000001, 234195255375503079690400057633265510581087082006817356924774723468294901747510352675631491470712754833859385753600000000000000000001

Offset: 1

Author

Artur Jasinski, Apr 07 2008

Keywords

• nonn

Comments

For numbers k for which (9+k!)/9 is prime see A137390.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..9

Crossrefs

Cf. A020458, A007749, A082672, A089085, A089130, A117141, A137390, A139056, A139057, A139058, A139059, A139060, A139061, A139062, A139063, A139064, A139065, A139066, A137390, A139070, A139071, A139072, A139156.

Programs

Mathematica

a = {}; Do[If[PrimeQ[(n! + 9)/9], AppendTo[a, (n! + 9)/9]], {n, 1, 150}]; a
Select[Range[100]!/9+1,PrimeQ] (* Harvey P. Dale, Aug 17 2017 *)

PARI

for(n=6,1e4,if(ispseudoprime(t=n!/9+1),print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011

Formula

a(n) = A139156(A137390(n)). - Amiram Eldar, Oct 14 2024