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 A371432 #10 Mar 23 2024 11:02:56
%S A371432 1,2,7,30,142,714,3740,20178,111325,625042,3559101,20502014,119249277,
%T A371432 699330360,4130235408,24543145310,146629131642,880184547880,
%U A371432 5305961255490,32107022363150,194947974895960,1187354222296110,7252099548616320,44408257163905050
%N A371432 Expansion of (1/x) * Series_Reversion( x * ((1-x)^2 + x^4) ).
%H A371432 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A371432 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+k,k) * binomial(3*n-2*k+1,n-4*k).
%o A371432 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^2+x^4))/x)
%o A371432 (PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(n+k, k)*binomial(3*n-2*k+1, n-4*k))/(n+1);
%Y A371432 Cf. A369124, A371435.
%Y A371432 Cf. A369160.
%K A371432 nonn
%O A371432 0,2
%A A371432 _Seiichi Manyama_, Mar 23 2024