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 A373685 #9 Jun 13 2024 08:16:14
%S A373685 1,1,1,7,73,301,1561,32131,306097,2062873,43102801,720515071,
%T A373685 7245589561,136364378437,3259345980073,47903339552251,873735377165281,
%U A373685 25383884535029041,515592396859327777,10003196649764818423,316630570292623967401,8359224513085985870941
%N A373685 Expansion of e.g.f. exp(x / (1 - x^3)^2) / (1 - x^3).
%F A373685 a(n) = n! * Sum_{k=0..floor(n/3)} binomial(2*n-5*k,k)/(n-3*k)!.
%F A373685 a(n) == 1 (mod 6).
%o A373685 (PARI) a(n) = n!*sum(k=0, n\3, binomial(2*n-5*k, k)/(n-3*k)!);
%Y A373685 Cf. A373680, A373684.
%K A373685 nonn
%O A373685 0,4
%A A373685 _Seiichi Manyama_, Jun 13 2024