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 A373521 #16 Jun 10 2024 10:03:37
%S A373521 1,1,1,1,1,91,541,1891,5041,249481,3424681,24365881,119821681,
%T A373521 4208219731,96849813061,1133147785771,8728726799521,251218306095121,
%U A373521 8116398738418321,138787857114672241,1523943014238675361,39648007379230971211,1599866285860593980461
%N A373521 Expansion of e.g.f. exp(x/(1 - x^4)^(3/4)).
%F A373521 a(n) = n! * Sum_{k=0..floor(n/4)} binomial(3*n/4-2*k-1,k)/(n-4*k)!.
%F A373521 a(n) == 1 mod 90.
%o A373521 (PARI) a(n) = n!*sum(k=0, n\4, binomial(3*n/4-2*k-1, k)/(n-4*k)!);
%Y A373521 Cf. A293507, A373519, A373520.
%Y A373521 Cf. A373526.
%K A373521 nonn
%O A373521 0,6
%A A373521 _Seiichi Manyama_, Jun 08 2024