A026935 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A008288.

1, 10, 75, 500, 3149, 19214, 115031, 680424, 3992921, 23305234, 135514019, 785892316, 4549048229, 26295995926, 151857925039, 876366840784, 5055045581745, 29148894792730, 168045778127355, 968679251764676, 5583525654107645, 32183666525389086, 185514611981021959

Offset

2,2

Links

G. C. Greubel, Table of n, a(n) for n = 2..500

Mathematica

A008288[n_, k_]:= Binomial[n, k]*Hypergeometric2F1[-k, k-n, -n, -1];
A026935[n_]:= Sum[A008288[n, k]*A008288[n, k+2], {k, 0, n-2}];
Table[A026935[n], {n, 2, 40}] (* G. C. Greubel, May 25 2021 *)

Prog

(Sage)
@CachedFunction
def A008288(n, k): return sum(binomial(n-j, j)*binomial(n-2*j, k-j) for j in (0..k))
def A026935(n): return sum(A008288(n, k)*A008288(n, k+2) for k in (0..n-2))
[A026935(n) for n in (2..40)] # G. C. Greubel, May 25 2021

Crossrefs

Cf. A008288.

Sequence in context: A305784 A053464 A111998 * A110127 A233657 A346842

Adjacent sequences: A026932 A026933 A026934 * A026936 A026937 A026938

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 17 2019

Status

approved