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 A371435 #10 Mar 23 2024 11:07:11
%S A371435 1,3,15,91,611,4368,32590,250821,1976441,15865465,129275835,
%T A371435 1066438399,8888818659,74743312480,633272709348,5400983817990,
%U A371435 46330852036920,399479717666693,3460229824525809,30095179524446946,262722158090170570,2301201197665717770
%N A371435 Expansion of (1/x) * Series_Reversion( x * ((1-x)^3 + x^4) ).
%H A371435 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A371435 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} (-1)^k * binomial(n+k,k) * binomial(4*n-k+2,n-4*k).
%o A371435 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*((1-x)^3+x^4))/x)
%o A371435 (PARI) a(n) = sum(k=0, n\4, (-1)^k*binomial(n+k, k)*binomial(4*n-k+2, n-4*k))/(n+1);
%Y A371435 Cf. A369124, A371432.
%Y A371435 Cf. A369161.
%K A371435 nonn
%O A371435 0,2
%A A371435 _Seiichi Manyama_, Mar 23 2024