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 A373668 #12 Jun 13 2024 08:16:01
%S A373668 1,1,1,19,73,901,7921,88831,1261009,15786793,284515201,4359416491,
%T A373668 88359404761,1671036171949,36734936604913,831051144091351,
%U A373668 19848996799904161,516144198653004241,13522792578340917889,391107276466207593283,11295497154349628317801
%N A373668 Expansion of e.g.f. exp(x / (1 - x^2)^3).
%F A373668 a(n) = n! * Sum_{k=0..floor(n/2)} binomial(3*n-5*k-1,k)/(n-2*k)!.
%F A373668 a(n) == 1 (mod 18).
%o A373668 (PARI) a(n) = n!*sum(k=0, n\2, binomial(3*n-5*k-1, k)/(n-2*k)!);
%Y A373668 Cf. A012150, A088009, A373619, A373620, A373667.
%Y A373668 Cf. A373653, A373682.
%K A373668 nonn
%O A373668 0,4
%A A373668 _Seiichi Manyama_, Jun 13 2024