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 A367029 #8 Nov 02 2023 10:40:27
%S A367029 1,1,0,-4,-10,2,89,249,-91,-2811,-8071,4201,103617,297201,-200421,
%T A367029 -4167581,-11798389,9803475,177275251,492087227,-488311177,
%U A367029 -7839760737,-21249466773,24651743523,356735365223,941396264159,-1257287146286,-16589782316762
%N A367029 G.f. satisfies A(x) = 1 + x*A(x) - x^2*A(x)^4.
%F A367029 a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(n+2*k,k) * binomial(n+k,n-2*k) / (3*k+1).
%o A367029 (PARI) a(n) = sum(k=0, n\2, (-1)^k*binomial(n+2*k, k)*binomial(n+k, n-2*k)/(3*k+1));
%Y A367029 Cf. A343773, A367028, A367030.
%K A367029 sign
%O A367029 0,4
%A A367029 _Seiichi Manyama_, Nov 02 2023