A231620 a(n) = A000930(n^2), where A000930 is Narayana's cows sequence.

1, 1, 3, 19, 277, 8641, 578949, 83316385, 25753389181, 17098272199297, 24382819596721629, 74684329652984094451, 491347682599497451569523, 6943240361573523613067995729, 210741152533202801182666172606913, 13738849457010997118546333815068560833, 1923823572225984354415961546862346889944243

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..75

Formula

a(n) = [x^(n^2)] 1 / (1 - x - x^3) for n>=0.

Mathematica

Table[SeriesCoefficient[1/(1 - x - x^3), {x, 0, n^2}], {n, 0, 25}] (* G. C. Greubel, Apr 26 2017 *)

Prog

(PARI) {a(n) = polcoeff(1/(1-x-x^3 + x*O(x^(n^2))), n^2)}
for(n=0, 20, print1(a(n), ", "))

Crossrefs

Cf. A000930, A231621, A228647, A228648.

Sequence in context: A173799 A003011 A338772 * A268646 A356512 A143597

Adjacent sequences: A231617 A231618 A231619 * A231621 A231622 A231623

Keyword

nonn

Author

Paul D. Hanna, Nov 13 2013

Status

approved