A243633 Expansion of (4*x^3-6*x^2+4*x-1)/(5*x^3-8*x^2+5*x-1).

1, 1, 3, 8, 21, 56, 152, 417, 1149, 3169, 8738, 24083, 66356, 182806, 503597, 1387317, 3821839, 10528644, 29005093, 79905508, 220130016, 606431481, 1670644817, 4602422317, 12679110454, 34929397819, 96226217048, 265091454958

Offset: 0

Author

Vladimir Kruchinin, Jun 08 2014

Keywords

• nonn

Crossrefs

cf. A038504

Programs

Maxima

a(n):=sum(sum(binomial(m+k-1,k)*binomial(n+m-1,n-4*k-m),k,0,n/2),m,0,n);

Formula

a(n) = sum(m=0..n, sum(k=0..n/2, binomial(m+k-1,k)*binomial(n+m-1,n-4*k-m))).

A(x) = 1/(1-F(x)), where F(x) is g.f. A038504.