A108209 a(n) = 5*(n-1)*a(n-1) -2*(n-1)*a(n-2) with a(0)=0, a(1)=2.

0, 2, 10, 92, 1320, 25664, 628400, 18544032, 640243520, 25313036288, 1127562249600, 55871851754240, 3048145476992000, 181547804177418240, 11721355489130393600, 815411545722159841280, 60804225264488076288000

Offset

0,2

Comments

This is also the negative of the (1,2) element of the product matrix after multiplying the unit matrix from the

left by the matrices (0,-2;j-1,5j-5) in the order j=2 to n.

Links

Table of n, a(n) for n=0..16.

Mathematica

M[n_] := {{0, -2}, {(n - 1), 5*(n - 1)}} v[1] = {0, 1} v[n_] := v[n] = M[n].v[n - 1] a = Table[Abs[v[n][[1]]], {n, 1, 25}]

Crossrefs

Cf. A000166.

Sequence in context: A108528 A181136 A182952 * A111773 A289020 A195415

Adjacent sequences: A108206 A108207 A108208 * A108210 A108211 A108212

Keyword

nonn,easy

Author

Roger L. Bagula, Jun 15 2005

Extensions

Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009

Status

approved