A117667 a(n) = n^n-n^(n-1)-n^(n-2)-n^(n-3)-...-n^3-n^2-n.

1, 2, 15, 172, 2345, 37326, 686287, 14380472, 338992929, 8888888890, 256780503551, 8105545862052, 277635514376233, 10257237069745862, 406615755353655135, 17216961135462248176, 775537745518440716417

Offset

1,2

Links

Christian N. K. Anderson, Table of n, a(n) for n = 1..100

Formula

a(n) = A000312(n) - A023037(n) + 1. - Michel Marcus, Apr 14 2015

A191690(n)+1. - Robert G. Wilson v, Apr 16 2015

Example

a(3) = 3^3-3^2-3 = 27-9-3 = 15.

Maple

a:=n->n^n-sum(n^j, j=1..n-1): seq(a(n), n=1..19); # Emeric Deutsch, Apr 16 2006

Mathematica

s[n_] := Sum[n^i, {i, 1, n - 1}]; Table[n^n - s[n], {n, 17}] (* Carlos Eduardo Olivieri, Apr 14 2015 *)
f[n_] := ((n - 2) n^n + n)/(n - 1); f[1] = 1; Array[f, 18] (* Robert G. Wilson v, Apr 15 2015 *)

Crossrefs

Cf. A000312 (n^n), A023037 (1+n+n^2+...n^(n-1)),

A001923, A031972.

Sequence in context: A262035 A264793 A228840 * A360483 A222920 A036080

Adjacent sequences: A117664 A117665 A117666 * A117668 A117669 A117670

Keyword

nonn

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 11 2006

Status

approved