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 A371645 #6 Mar 31 2024 07:51:02
%S A371645 1,2,80640,516287415629905920000,
%T A371645 135851139773030831011345707357554182190215987200000000000
%N A371645 a(n) = Product_{k=0..n} (2*k^2)!.
%C A371645 The next term has 121 digits.
%F A371645 a(n) ~ c * 2^(2*n^3/3 + n^2 + 4*n/3) * Pi^(n/2) * n^(4*n^3/3 + 2*n^2 + 5*n/3 + 1/2) / exp(10*n^3/9 + n^2 + n), where c = 3.03114159524498232897099596239043047625469924617878376047699145874714076...
%t A371645 Table[Product[(2*k^2)!, {k, 0, n}], {n, 0, 6}]
%Y A371645 Cf. A255322.
%K A371645 nonn
%O A371645 0,2
%A A371645 _Vaclav Kotesovec_, Mar 31 2024