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 A371433 #11 Mar 23 2024 11:04:19
%S A371433 1,2,5,11,11,-77,-704,-3795,-15686,-48598,-74009,376623,4438840,
%T A371433 27458060,126898948,440550682,849522927,-2621906045,-39993434701,
%U A371433 -270428078305,-1339005344985,-5014789377825,-11407684195950,18849058485855,417417757017612,3058172078113944
%N A371433 Expansion of (1/x) * Series_Reversion( x * ((1-x)^3 + x) ).
%H A371433 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A371433 a(n) = (1/(n+1)) * Sum_{k=0..n} (-1)^k * binomial(n+k,k) * binomial(4*n+2*k+2,n-k).
%o A371433 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^3+x))/x)
%o A371433 (PARI) a(n) = sum(k=0, n, (-1)^k*binomial(n+k, k)*binomial(4*n+2*k+2, n-k))/(n+1);
%Y A371433 Cf. A371434, A371435.
%Y A371433 Cf. A369215.
%K A371433 sign
%O A371433 0,2
%A A371433 _Seiichi Manyama_, Mar 23 2024