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 A372108 #7 Apr 19 2024 10:31:01
%S A372108 1,3,21,174,1569,14898,146541,1479198,15231207,159338433,1688597850,
%T A372108 18089117742,195559863960,2130853276767,23377139412366,
%U A372108 258005735979357,2862644731044960,31912076884938312,357256970492137149,4014802252108301061,45274175730663116394
%N A372108 G.f. A(x) satisfies A(x) = 1/( 1 - 9*x/(1 - x*A(x)) )^(1/3).
%F A372108 a(n) = Sum_{k=0..n} 9^k * binomial(n/3+2*k/3-2/3,k) * binomial(n-1,n-k)/(n-k+1).
%o A372108 (PARI) a(n) = sum(k=0, n, 9^k*binomial(n/3+2*k/3-2/3, k)*binomial(n-1, n-k)/(n-k+1));
%Y A372108 Cf. A372089.
%K A372108 nonn
%O A372108 0,2
%A A372108 _Seiichi Manyama_, Apr 19 2024