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 A358364 #17 Nov 15 2023 03:13:12
%S A358364 1,20,324,5200,83300,1333584,21344400,341580096,5466017700,
%T A358364 87464462800,1399525960976,22393543798080,358310523944464,
%U A358364 5733141459080000,91732470946920000,1467748145667974400,23484346290765886500,375754541311565499600,6012139892071344570000
%N A358364 a(n) = 16^n * Sum_{k=0..n} binomial(1/2, k)^2.
%F A358364 a(n) = (16*n + 4)*(2*n - 1)^2*a(n - 1) / ((4*n - 3) * n^2).
%F A358364 G.f.: hypergeom([-1/2, -1/2], [1], 16*x)/(1 - 16*x).
%F A358364 a(n) ~ 2^(4*n+2) / Pi. - _Vaclav Kotesovec_, Nov 14 2023
%p A358364 a := n -> 16^n*add(binomial(1/2, k)^2, k = 0..n):
%p A358364 seq(a(n), n = 0..18);
%t A358364 a[n_] := 16^n * Sum[Binomial[1/2, k]^2, {k, 0, n}]; Array[a, 19, 0] (* _Amiram Eldar_, Nov 12 2022 *)
%Y A358364 Cf. A358362, A358363, A358365, A367332.
%K A358364 nonn
%O A358364 0,2
%A A358364 _Peter Luschny_, Nov 12 2022