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 A367943 #6 Dec 07 2023 02:19:49
%S A367943 1,5,13600,294372000000,252880261890048000000000,
%T A367943 27099784799070466617992871936000000000000,
%U A367943 882065676199020188908312950703217787436793856000000000000000000
%N A367943 a(n) = Product_{i=1..n, j=1..n} (i^2 + 4*j^2).
%F A367943 a(n) ~ c * n^(2*n^2 - 1/2) * 5^(n*(n+1)) * 2^(-n) * exp(n*(n+1)*(2*Pi - 3*arctan(2))/2 - 3*n^2) , where c = 0.4523180383519335764034720087114905921141637339852374451758854101884791581...
%t A367943 Table[Product[i^2+4*j^2, {i, 1, n}, {j, 1, n}], {n, 0, 8}]
%Y A367943 Cf. A324403, A367941, A367942, A367944.
%Y A367943 Cf. A367542, A367543.
%K A367943 nonn
%O A367943 0,2
%A A367943 _Vaclav Kotesovec_, Dec 05 2023