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 A379173 #10 Dec 17 2024 10:12:23
%S A379173 1,3,11,53,284,1630,9794,60830,387390,2515892,16599051,110943779,
%T A379173 749603067,5111606801,35133394554,243146923574,1692918638012,
%U A379173 11850006727400,83341778073920,588646472669454,4173607638548291,29694593381322531,211941668053441490,1517087043428034420
%N A379173 G.f. A(x) satisfies A(x) = (1 + x)/(1 - x*A(x))^2.
%F A379173 a(n) = Sum_{k=0..n} binomial(n-k+1,k) * binomial(3*n-3*k+1,n-k)/(n-k+1).
%o A379173 (PARI) a(n) = sum(k=0, n, binomial(n-k+1, k)*binomial(3*n-3*k+1, n-k)/(n-k+1));
%Y A379173 Cf. A003169, A249924, A379174.
%Y A379173 Cf. A025227, A379171.
%K A379173 nonn
%O A379173 0,2
%A A379173 _Seiichi Manyama_, Dec 17 2024