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 A366089 #12 Sep 29 2023 09:27:47
%S A366089 1,2,7,30,142,715,3756,20349,112864,637659,3656775,21229923,124531256,
%T A366089 736920158,4393859967,26371222935,159193382812,965923527255,
%U A366089 5887659026592,36034716884127,221362690616841,1364404640452602,8435444693847402
%N A366089 Expansion of (1/x) * Series_Reversion( x*(1-x)^3/(1-x-x^4) ).
%H A366089 Seiichi Manyama, <a href="/A366089/b366089.txt">Table of n, a(n) for n = 0..1000</a>
%F A366089 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+1,k) * binomial(3*n-3*k+1,n-4*k).
%o A366089 (PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(n+1, k)*binomial(3*n-3*k+1, n-4*k))/(n+1);
%Y A366089 Cf. A366086, A366087, A366088, A366090.
%Y A366089 Cf. A366055.
%K A366089 nonn
%O A366089 0,2
%A A366089 _Seiichi Manyama_, Sep 28 2023