A127231 a(n) = (2n)! + 1.
2, 3, 25, 721, 40321, 3628801, 479001601, 87178291201, 20922789888001, 6402373705728001, 2432902008176640001, 1124000727777607680001, 620448401733239439360001, 403291461126605635584000001, 304888344611713860501504000001, 265252859812191058636308480000001
Offset: 0
Keywords
Programs
-
Mathematica
Array[(2#)!+1&,16,0] (* James C. McMahon, Dec 30 2024 *)
Extensions
Entry revised by N. J. A. Sloane, Mar 26 2021