A369509 Expansion of (1/x) * Series_Reversion( x * ((1-x)^2-x)^2 ).

1, 6, 61, 756, 10406, 152880, 2348164, 37250298, 605592377, 10036783746, 168947499695, 2880456168330, 49638925087101, 863251245610368, 15130529347412496, 267011151724625220, 4740245924729076390, 84599747038748783220, 1516992745930706932654

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Index entries for reversions of series

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(2*n+k+1,k) * binomial(5*n+k+3,n-k).

Prog

(PARI) my(N=20, x='x+O('x^N)); Vec(serreverse(x*((1-x)^2-x)^2)/x)
(PARI) a(n) = sum(k=0, n, binomial(2*n+k+1, k)*binomial(5*n+k+3, n-k))/(n+1);

Crossrefs

Cf. A369510, A369511.

Sequence in context: A236670 A142970 A034659 * A064088 A342110 A191803

Adjacent sequences: A369506 A369507 A369508 * A369510 A369511 A369512

Keyword

nonn

Author

Seiichi Manyama, Jan 25 2024

Status

approved