A202423 Numbers n such that n!*n!! + 1 is prime.

1, 2, 3, 4, 5, 14, 37, 48, 50, 52, 88, 223

Offset

1,2

Links

Table of n, a(n) for n=1..12.

Example

For n = 3, 3!*3!! + 1 = 6*3 + 1 = 19 is prime.

Mathematica

lst={}; Do[If[PrimeQ[n!*n!!+1], AppendTo[lst, n]], {n, 500}]; lst

Crossrefs

Cf. A000142, A006882, A202422.

Sequence in context: A361947 A037340 A199165 * A171593 A227535 A096774

Adjacent sequences: A202420 A202421 A202422 * A202424 A202425 A202426

Keyword

nonn

Author

Michel Lagneau, Dec 19 2011

Status

approved