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 A324566 #4 Mar 08 2019 03:01:45
%S A324566 2,72,2709504,15637972132823040,2676716427588188879089135779840000,
%T A324566 2844659827809077182003221596452154340416256794895644098560000
%N A324566 a(n) = Product_{i=0..n, j=0..n} (binomial(2*i, i) + binomial(2*j, j)).
%F A324566 a(n) ~ c * d^n * 2^(4*n^3/3 + 3*n^2) * exp(n^2/4 + n) / (Pi^(n^2/2) * n^(n^2/2 + n + alfa), where
%F A324566 d = 1.7552437670085151253596298317411616254914764275962173772854884197280838467...
%F A324566 alfa = 0.0720289309157636194865104906223497131817905230497828189113545663815669...
%F A324566 c = 1.3392511999007422713775779654793976642559410116533455108049762435308676715...
%t A324566 Table[Product[Binomial[2*i, i] + Binomial[2*j, j], {i, 0, n}, {j, 0, n}], {n, 0, 7}]
%Y A324566 Cf. A000984, A007685, A324565, A324567.
%K A324566 nonn
%O A324566 0,1
%A A324566 _Vaclav Kotesovec_, Mar 07 2019