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 A371523 #11 Mar 26 2024 11:15:15
%S A371523 1,2,15,142,1533,17924,220936,2827218,37202580,500228562,6842899886,
%T A371523 94931338876,1332438761910,18887047322030,269986427261981,
%U A371523 3887654399820062,56337997080499605,821021578186212094,12024687038651388155,176900548019426869808,2612917215947948178941
%N A371523 G.f. A(x) satisfies A(x) = (1 + x*A(x)^3 / (1-x))^2.
%F A371523 a(n) = 2 * Sum_{k=0..n} binomial(n-1,n-k) * binomial(6*k+1,k)/(5*k+2).
%F A371523 G.f.: A(x) = B(x)^2 where B(x) is the g.f. of A349333.
%o A371523 (PARI) a(n) = 2*sum(k=0, n, binomial(n-1, n-k)*binomial(6*k+1, k)/(5*k+2));
%Y A371523 Cf. A349333, A371379, A371519, A371521, A371522.
%Y A371523 Cf. A270386, A371518.
%K A371523 nonn
%O A371523 0,2
%A A371523 _Seiichi Manyama_, Mar 26 2024