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 A371607 #12 Mar 30 2024 02:37:24
%S A371607 1,2,3,10,29,92,314,1078,3830,13844,50746,188554,707667,2679960,
%T A371607 10227940,39294772,151859858,589943516,2302462140,9023681820,
%U A371607 35498194465,140122652960,554827907272,2203135245820,8771143399104,35003747271444,140002994665366
%N A371607 G.f. satisfies A(x) = ( 1 + x * (1 + x*A(x)^2) )^2.
%F A371607 a(n) = Sum_{k=0..n} binomial(4*(n-k)+2,k) * binomial(k,n-k)/(2*(n-k)+1).
%F A371607 G.f.: A(x) = B(x)^2 where B(x) is the g.f. of A137954.
%o A371607 (PARI) a(n, r=2, s=1, t=0, u=4) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+r));
%Y A371607 Cf. A137954, A371612.
%K A371607 nonn
%O A371607 0,2
%A A371607 _Seiichi Manyama_, Mar 29 2024