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 A372089 #7 Apr 18 2024 09:31:57
%S A372089 1,3,21,171,1512,14040,134775,1325457,13279329,135014931,1389328200,
%T A372089 14440275000,151366896639,1598281697205,16983592285797,
%U A372089 181478066048739,1948770301135167,21018820972926429,227600123488744275,2473358642698093245,26965560597470251857
%N A372089 G.f. A(x) satisfies A(x) = 1/( 1 - 9*x*(1 + x*A(x)) )^(1/3).
%F A372089 a(n) = Sum_{k=0..n} 9^k * binomial(n/3+2*k/3-2/3,k) * binomial(k,n-k)/(n-k+1).
%o A372089 (PARI) a(n) = sum(k=0, n, 9^k*binomial(n/3+2*k/3-2/3, k)*binomial(k, n-k)/(n-k+1));
%Y A372089 Cf. A372003.
%K A372089 nonn
%O A372089 0,2
%A A372089 _Seiichi Manyama_, Apr 17 2024