A127231 a(n) = (2n)! + 1.

2, 3, 25, 721, 40321, 3628801, 479001601, 87178291201, 20922789888001, 6402373705728001, 2432902008176640001, 1124000727777607680001, 620448401733239439360001, 403291461126605635584000001, 304888344611713860501504000001, 265252859812191058636308480000001

Offset

0,1

Links

Table of n, a(n) for n=0..15.

Mathematica

Array[(2#)!+1&, 16, 0] (* James C. McMahon, Dec 30 2024 *)

Crossrefs

a(n) = 1 + A010050(n).

Cf. A000142, A028387, A062938, A127227, A127228, A127229, A127230.

Sequence in context: A094998 A208203 A109586 * A060371 A358390 A130975

Adjacent sequences: A127228 A127229 A127230 * A127232 A127233 A127234

Keyword

nonn

Author

Artur Jasinski, Jan 09 2007

Extensions

Entry revised by N. J. A. Sloane, Mar 26 2021

Status

approved