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 A370841 #10 Mar 03 2024 09:52:48
%S A370841 1,1,2,5,13,35,96,264,719,1914,4888,11583,23540,29907,-57120,-695742,
%T A370841 -3938275,-18266657,-76983710,-306116660,-1168987469,-4327878214,
%U A370841 -15617536020,-55097816085,-190320077663,-643865817117,-2131713980560,-6893257768141
%N A370841 Expansion of (1/x) * Series_Reversion( x * (1/(1-x^4) - x) ).
%H A370841 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A370841 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(2*n-4*k+1,k) * binomial(2*n-4*k,n-4*k).
%o A370841 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1/(1-x^4)-x))/x)
%o A370841 (PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(2*n-4*k+1, k)*binomial(2*n-4*k, n-4*k))/(n+1);
%Y A370841 Cf. A370839, A370840.
%Y A370841 Cf. A369631.
%K A370841 sign
%O A370841 0,3
%A A370841 _Seiichi Manyama_, Mar 03 2024