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 A367260 #7 Nov 11 2023 13:55:38
%S A367260 1,1,6,36,251,1881,14817,120950,1014042,8680377,75552553,666614637,
%T A367260 5948817600,53599239101,486926148000,4455202562652,41018936164660,
%U A367260 379747493741643,3532914858433284,33012260400580342,309692626084981245,2915659701275923491
%N A367260 G.f. satisfies A(x) = 1 + x*A(x)^3 * (1 + x*A(x))^3.
%F A367260 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 A367260 (PARI) a(n, s=3, t=3, u=1) = sum(k=0, n, binomial(t*k+u*(n-k)+1, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+1));
%Y A367260 Cf. A019497, A361305, A364742.
%Y A367260 Cf. A367233.
%K A367260 nonn
%O A367260 0,3
%A A367260 _Seiichi Manyama_, Nov 11 2023