A144046 Numbers k such that |k! - 107| and |k! + 107| are prime.

3, 4, 5, 6, 7, 8, 80

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Formula

5 is a term since 5! - 107 = 13 and 5! + 107 = 227, both prime.

Mathematica

lst={}; a=107; Do[If[PrimeQ[n!-a]&&PrimeQ[n!+a], AppendTo[lst, n]], {n, 0, 20^2}]; lst

Prog

(PARI) for(n=1, 106, if(ispseudoprime(abs(n!-107))&&ispseudoprime(n!+107), print1(n", "))) \\ Charles R Greathouse IV, Oct 05 2011

Crossrefs

Sequence in context: A037349 A037350 A014615 * A210934 A354774 A194276

Adjacent sequences: A144043 A144044 A144045 * A144047 A144048 A144049

Keyword

nonn,fini,full

Author

Vladimir Joseph Stephan Orlovsky, Sep 08 2008

Status

approved