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 A379328 #9 Dec 21 2024 11:10:12
%S A379328 1,2,8,44,272,1808,12616,91136,675712,5112576,39316480,306402304,
%T A379328 2414543328,19207303168,154030314752,1243912552448,10107398806016,
%U A379328 82573989969920,677862373390592,5588755066388480,46257005500080128,384210240316375040,3201482490107076608
%N A379328 G.f. A(x) satisfies A(x) = sqrt( (1 + 2*x*A(x)^3) * (1 + 2*x*A(x)) ).
%F A379328 a(n) = 2^n * Sum_{k=0..n} binomial(n/2+k+1/2,k) * binomial(n/2+k+1/2,n-k)/(n+2*k+1).
%o A379328 (PARI) a(n) = 2^n*sum(k=0, n, binomial(n/2+k+1/2, k)*binomial(n/2+k+1/2, n-k)/(n+2*k+1));
%Y A379328 Cf. A379326, A379327.
%Y A379328 Cf. A198953, A379280.
%K A379328 nonn
%O A379328 0,2
%A A379328 _Seiichi Manyama_, Dec 21 2024