A144637 Column 2 of triangle in A144633.

0, 0, 1, -3, 11, -45, 175, -315, -6265, 139755, -2127125, 28153125, -327452125, 2921393475, -2998820825, -788463550875, 28464750689375, -739460838241125, 16173782241491875, -294957734383186875, 3672958879661946875, 19544468129733421875, -3601613031568517590625

Offset

0,4

Links

Alois P. Heinz, Table of n, a(n) for n = 0..100

Formula

E.g.f.: B(x)^2/2 where B(x) is e.g.f. for A144636. [Vladeta Jovovic, Jan 24 2009]

Maple

A:= proc(n, k) option remember; if n=k then 1 elif k<n or n<1 then 0 else A(n-1, k-1) +(k-1) *A(n-1, k-2) +(k-1) *(k-2) *A(n-1, k-3)/2 fi end: M:= proc(n) option remember; Matrix(n+1, (i, j)-> A(i-1, j-1))^(-1) end: a:= n-> M (n+2)[3, n+1]: seq (a(n), n=0..25); # Alois P. Heinz, Oct 25 2009

Mathematica

max = 22; t[n_, n_] = 1; t[n_ /; n >= 0, k_] /; (0 <= k <= 3*n) := t[n, k] = t[n-1, k-1] + (k-1)*t[n-1, k-2] + (1/2)*(k-1)*(k-2)*t[n-1, k-3]; t[_, _] = 0; A144633 = Table[t[n, k], {n, 0, max}, {k, 0, max}] // Inverse // Transpose ; A144633[[All, 3]] (* Jean-François Alcover, Jan 17 2014 *)

Crossrefs

Cf. A144633.

Sequence in context: A030844 A030959 A073590 * A369839 A151109 A151110

Adjacent sequences: A144634 A144635 A144636 * A144638 A144639 A144640

Keyword

sign

Author

N. J. A. Sloane, Jan 23 2009

Extensions

More terms from Alois P. Heinz, Oct 25 2009

Status

approved