A127688 a(n) = (n+1)^n - n!!.

0, 1, 7, 61, 617, 7761, 117601, 2097047, 43046337, 999999055, 25937420761, 743008360293, 23298085076401, 793714773119009, 29192926024745505, 1152921504604819951, 48661191875656546561, 2185911559738662072543, 104127350297911055738281, 5242879999999999345270925

Offset

0,3

Comments

Theorem: (n+1)^n > n!! for n>0.

References

D. S. Mitrinovic, Analytic Inequalities, Springer-Verlag, 1970; p. 192, 3.1.15.

Links

Michael De Vlieger, Table of n, a(n) for n = 0..386

Maple

seq((n+1)^n - doublefactorial(n), n=0..10); # Georg Fischer, Apr 10 2024

Mathematica

Table[(n+1)^n - (n)!!, {n, 0, 10}] (* Georg Fischer, Apr 10 2024 *)

Crossrefs

Cf. A000165, A127650.

Sequence in context: A077642 A071172 A259335 * A111532 A379996 A061634

Adjacent sequences: A127685 A127686 A127687 * A127689 A127690 A127691

Keyword

nonn

Author

N. J. A. Sloane, Apr 03 2007

Extensions

Formula changed by Georg Fischer, Apr 10 2024

Status

approved