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 A367941 #7 Dec 07 2023 02:20:26
%S A367941 1,3,1944,4102777008,140890630179993255936,
%T A367941 247470977313135626800897828778803200,
%U A367941 54132901224855040835735917614114353691165557521593139200
%N A367941 a(n) = Product_{i=1..n, j=1..n} (i^2 + 2*j^2).
%F A367941 a(n) ~ c * n^(2*n^2 - 1/2) * 3^(n*(n+1)) * 2^(-n/2) * exp(n*(n+1)*(Pi - arctan(sqrt(2))) / sqrt(2) - 3*n^2) , where c = 0.4690673220228472212446336926899602910226601891141458824921925169726804439...
%t A367941 Table[Product[i^2+2*j^2, {i, 1, n}, {j, 1, n}], {n, 0, 8}]
%Y A367941 Cf. A324403, A367942, A367943, A367944.
%Y A367941 Cf. A367542, A367543.
%K A367941 nonn
%O A367941 0,2
%A A367941 _Vaclav Kotesovec_, Dec 05 2023