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 A373680 #11 Jun 13 2024 08:16:09
%S A373680 1,1,1,1,49,241,721,16801,204961,1276129,19968481,417479041,
%T A373680 4522597201,62399971921,1685741065009,28122880050721,415551065616961,
%U A373680 12085752936331201,281057646411506881,4923299166925874689,143004800073025326961,4244797186148550210481
%N A373680 Expansion of e.g.f. exp(x / (1 - x^3)^2).
%F A373680 a(n) = n! * Sum_{k=0..floor(n/3)} binomial(2*n-5*k-1,k)/(n-3*k)!.
%F A373680 a(n) == 1 (mod 48).
%o A373680 (PARI) a(n) = n!*sum(k=0, n\3, binomial(2*n-5*k-1, k)/(n-3*k)!);
%Y A373680 Cf. A293493, A373517, A373518.
%Y A373680 Cf. A373654, A373685.
%K A373680 nonn
%O A373680 0,5
%A A373680 _Seiichi Manyama_, Jun 13 2024