0,4

McCombinations: in 2002, McDonald's advertised a McChoice menu of 8 items under the heading "40,312 combinations" rather than the more obvious 2^8-1=255 (A000225). The Advertising Standards Authority "considered that the number quoted in the advertisement was not necessarily so exaggerated as to be misleading". - Henry Bottomley, May 01 2003

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Advertising Standards Authority, McDonald's Restaurants Ltd (archived May 10 2004).

a(n) = n*a(n-1)+n(n-2) = n*A033312(n-1) = A000142(n)-n. - Henry Bottomley, May 01 2003

E.g.f.: 1/(1 - x) - x*exp(x). - Ilya Gutkovskiy, Jan 27 2017

A005096:=n->n!-n: seq(A005096(n), n=0..25); # Wesley Ivan Hurt, Oct 28 2014

lst={}; Do[AppendTo[lst, n!-n], {n, 3*4!}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 20 2008 *)

Table[n! - n, {n, 0, 25}] (* Wesley Ivan Hurt, Oct 28 2014 *)

(Magma) [Factorial(n) - n: n in [0..25]]; // Vincenzo Librandi, Jul 20 2011

(PARI) a(n)=n!-n \\ Charles R Greathouse IV, Oct 28 2014

Cf. A000142, A033312.

Sequence in context: A178711 A257067 A108911 * A275796 A164535 A001652

Adjacent sequences: A005093 A005094 A005095 * A005097 A005098 A005099

approved