A026936 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A008288.

1, 14, 131, 1028, 7333, 49362, 319943, 2020552, 12526153, 76603094, 463676491, 2784550604, 16619355501, 98706690714, 583943891087, 3443573355152, 20254044891793, 118871039217822, 696401860980499, 4073713439171732, 23799679604123189, 138895001298962786, 809854583626750039

Offset

3,2

Links

G. C. Greubel, Table of n, a(n) for n = 3..1000

Mathematica

A008288[n_, k_]:= Binomial[n, k]*Hypergeometric2F1[-k, k-n, -n, -1];
A026936[n_]:= Sum[A008288[n, k]*A008288[n, k+3], {k, 0, n-3}];
Table[A026936[n], {n, 3, 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 A026936(n): return sum(A008288(n, k)*A008288(n, k+3) for k in (0..n-3))
[A026936(n) for n in (3..40)] # G. C. Greubel, May 25 2021

Crossrefs

Cf. A008288.

Sequence in context: A006565 A206207 A358168 * A021114 A328785 A375894

Adjacent sequences: A026933 A026934 A026935 * A026937 A026938 A026939

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 17 2019

Status

approved