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 A367284 #8 Nov 12 2023 04:36:16
%S A367284 1,1,4,19,107,648,4144,27500,187654,1308361,9280049,66749995,
%T A367284 485741501,3569653591,26454406231,197482954338,1483619134872,
%U A367284 11208536870979,85101381927454,649017399223259,4969510058193925,38189305411228229,294440263583908772
%N A367284 G.f. satisfies A(x) = 1 + x*A(x) * (1 + x*A(x)^3)^3.
%F A367284 If g.f. satisfies A(x) = 1 + x*A(x)^t * (1 + x*A(x)^u)^s, then a(n) = Sum_{k=0..n} binomial(t*k+u*(n-k)+1,k) * binomial(s*k,n-k) / (t*k+u*(n-k)+1).
%o A367284 (PARI) a(n, s=3, t=1, u=3) = sum(k=0, n, binomial(t*k+u*(n-k)+1, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+1));
%Y A367284 Cf. A002293, A099234, A364742, A367261.
%K A367284 nonn
%O A367284 0,3
%A A367284 _Seiichi Manyama_, Nov 12 2023