A173319 a(n) = 5*n! + 1.

6, 6, 11, 31, 121, 601, 3601, 25201, 201601, 1814401, 18144001, 199584001, 2395008001, 31135104001, 435891456001, 6538371840001, 104613949440001, 1778437140480001, 32011868528640001, 608225502044160001, 12164510040883200001, 255454710858547200001

Offset: 0

Author

Vincenzo Librandi, Feb 16 2010

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

Cf. sequences of the type k*n!+1: A038507 (k=1), A052898 (k=2), A173324 (k=3), A173322 (k=4), this sequence, A173314 (k=6).

Programs

Magma

[5*Factorial(n) + 1: n in [0..20]]; // Vincenzo Librandi, Sep 28 2013

Magma

[6] cat [n eq 1 select n+5 else n*Self(n-1)-n+1: n in [1..25] ]; // Vincenzo Librandi, Sep 28 2013

Maple

A173319:=n->5*n!+1: seq(A173319(n), n=0..20); # Wesley Ivan Hurt, Oct 10 2014

Mathematica

Table[5 n! + 1, {n, 0, 20}] (* Vincenzo Librandi, Sep 28 2013 *)

Formula

a(0)=6; for n>0, a(n) = n*a(n-1)-n+1. - Vincenzo Librandi, Sep 28 2013

(n-2)*a(n) - (n^2-n-1)*a(n-1) + (n-1)^2*a(n-2) = 0. [Bruno Berselli, Sep 28 2013]