A363816 G.f. satisfies A(x) = (1 + x/A(x))/(1 - x)^2.

1, 3, 2, 8, -9, 62, -230, 1054, -4753, 22208, -105419, 508396, -2482284, 12248430, -60980860, 305955372, -1545397447, 7852100312, -40105277621, 205798130624, -1060467961487, 5485199090834, -28469067353663, 148220323891484, -773892318396664, 4051261817405034

Offset

0,2

Links

Paolo Xausa, Table of n, a(n) for n = 0..1000

Formula

G.f.: A(x) = -2*x / (1-sqrt(1+4*x*(1-x)^2)).

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

Mathematica

A363816[n_]:=(-1)^(n-1)Sum[Binomial[2k-1, k]Binomial[2(k-1), n-k]/(2k-1), {k, 0, n}]; Array[A363816, 30, 0] (* Paolo Xausa, Oct 20 2023 *)

Prog

(PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(2*k-1, k)*binomial(2*(k-1), n-k)/(2*k-1));

Crossrefs

Partial sums of A366356.

Cf. A162477, A363818, A364629, A364630.

Cf. A363817, A366363.

Sequence in context: A195055 A214683 A371998 * A060921 A163356 A209360

Adjacent sequences: A363813 A363814 A363815 * A363817 A363818 A363819

Keyword

sign

Author

Seiichi Manyama, Oct 18 2023

Status

approved