A231620 - OEIS

%I #11 Apr 26 2017 22:58:21

%S 1,1,3,19,277,8641,578949,83316385,25753389181,17098272199297,

%T 24382819596721629,74684329652984094451,491347682599497451569523,

%U 6943240361573523613067995729,210741152533202801182666172606913,13738849457010997118546333815068560833,1923823572225984354415961546862346889944243

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

%H G. C. Greubel, <a href="/A231620/b231620.txt">Table of n, a(n) for n = 0..75</a>

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

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

%o (PARI) {a(n) = polcoeff(1/(1-x-x^3 + x*O(x^(n^2))), n^2)}

%o for(n=0, 20, print1(a(n), ", "))

%Y Cf. A000930, A231621, A228647, A228648.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Nov 13 2013