This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A376783 #14 Oct 04 2024 06:15:50
%S A376783 1,0,1,0,1,1,1,4,1,9,2,16,10,25,37,37,101,65,226,164,443,481,810,1325,
%T A376783 1522,3258,3251,7236,7926,15010,20234,30557,50234,64501,117966,145557,
%U A376783 263107,346293,569726,835909,1233943,1984730,2740492,4579704,6288323,10311571
%N A376783 Expansion of 1/sqrt((1 - x^2 - x^5)^2 - 4*x^7).
%F A376783 G.f.: 1/sqrt((1 - x^2 + x^5)^2 - 4*x^5) = 1/sqrt((1 + x^2 - x^5)^2 - 4*x^2).
%o A376783 (PARI) my(N=50, x='x+O('x^N)); Vec(1/sqrt((1-x^2-x^5)^2-4*x^7))
%o A376783 (PARI) a(n) = sum(k=0, n\5, ((n-3*k)%2==0)*binomial((n-3*k)/2, k)^2);
%Y A376783 Cf. A246884, A376722, A376784.
%Y A376783 Cf. A001687.
%K A376783 nonn
%O A376783 0,8
%A A376783 _Seiichi Manyama_, Oct 04 2024