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 A365122 #12 Dec 06 2024 06:59:34
%S A365122 1,3,12,64,372,2319,15105,101649,701073,4929657,35207220,254690517,
%T A365122 1862325262,13742311074,102204992352,765328009950,5765316776550,
%U A365122 43661497944861,332217854059362,2538540859615095,19471592691620310,149871698475060433,1157188723053901449
%N A365122 G.f. A(x) satisfies A(x) = (1 + x / (1 - x*A(x))^3)^3.
%F A365122 If g.f. satisfies A(x) = (1 + x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*(n-k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).
%F A365122 G.f.: A(x) = B(x)^3 where B(x) is the g.f. of A371616. - _Seiichi Manyama_, Dec 06 2024
%o A365122 (PARI) a(n, s=3, t=3) = sum(k=0, n, binomial(t*(n-k+1), k)*binomial(n+(s-1)*k-1, n-k)/(n-k+1));
%Y A365122 Cf. A006013, A365113.
%Y A365122 Cf. A365119, A365121.
%Y A365122 Cf. A371616.
%K A365122 nonn
%O A365122 0,2
%A A365122 _Seiichi Manyama_, Aug 22 2023