A056590 Fourth column sequence of triangle A056588.

1, 7, 53, 318, 1784, 9288, 46233, 221859, 1036585, 4742650, 21350264, 94895016, 417562385, 1822824255, 7907350365, 34130697462, 146735898760, 628870859320, 2688466352825, 11470754475675, 48865641344081, 207913415718642

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Formula

a(n)= A056588(n+3, 3), n >= 0.

a(n)= 3^(n+4)-F(n+5)*2^(n+4)+(F(n+3)-2)*F(n+5)*F(n+4)/2; F(n)=A000045(n) (Fibonacci).

G.f.:(1-3*x+8*x^2-3*x^3-3*x^4-4*x^5)/((1+x)*(1-3*x)*(1+x-x^2)*(1-2*x-4*x^2)*(1-3*x+x^2)*(1-4*x-x^2)).

Crossrefs

Cf. A000045, A056588, A000012, A000071, A056589.

Sequence in context: A352459 A141911 A200766 * A223778 A223712 A065542

Adjacent sequences: A056587 A056588 A056589 * A056591 A056592 A056593

Keyword

nonn,easy

Author

Wolfdieter Lang Jul 10 2000

Status

approved