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 A366087 #8 Sep 28 2023 12:07:50 %S A366087 1,0,0,0,-1,-1,-1,-1,3,8,14,21,7,-40,-134,-291,-389,-188,710,2906, %T A366087 6285,8931,5477,-15250,-66359,-149426,-224524,-154288,336695,1605033, %U A366087 3774375,5887736,4504451,-7603388,-40495514,-98834842,-159804251,-134317549,173843349,1050099387 %N A366087 Expansion of (1/x) * Series_Reversion( x*(1-x)/(1-x-x^4) ). %F A366087 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+1,k) * binomial(n-3*k-1,n-4*k). %o A366087 (PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(n+1, k)*binomial(n-3*k-1, n-4*k))/(n+1); %Y A366087 Cf. A366086, A366088, A366089, A366090. %K A366087 sign %O A366087 0,9 %A A366087 _Seiichi Manyama_, Sep 28 2023