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 A365981 #10 Sep 24 2023 09:16:39
%S A365981 1,0,0,2,0,0,80,720,0,13440,345600,3628800,5913600,296524800,
%T A365981 7062681600,92559667200,442810368000,18037334016000,459627769036800,
%U A365981 7475081822208000,65867064606720000,2634706112643072000,74102151110787072000,1464478283948359680000
%N A365981 Expansion of e.g.f. 1 / ( 1 - Sum_{k>=0} x^(4*k+3) / (4*k+3) ).
%F A365981 a(0) = 1; a(n) = Sum_{k=0..floor((n-3)/4)} (4*k+2)! * binomial(n,4*k+3) * a(n-4*k-3).
%o A365981 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1-sum(k=0, N\4, x^(4*k+3)/(4*k+3)))))
%Y A365981 Cf. A355284, A365980, A365982.
%Y A365981 Cf. A365911.
%K A365981 nonn
%O A365981 0,4
%A A365981 _Seiichi Manyama_, Sep 24 2023