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 A203675 #12 Nov 26 2023 04:07:46
%S A203675 1,13,57889,560058939856,42130404012097952586256,
%T A203675 65111467563626175389271488157658681344,
%U A203675 4528499444374253250530486688998183592108605307719698157568
%N A203675 Vandermonde sequence using x^2 - xy + y^2 applied to (1,4,9,...,n^2).
%C A203675 See A093883 for a discussion and guide to related sequences.
%F A203675 a(n) ~ c * (2 + sqrt(3))^(sqrt(3)*n*(n+1)/2) * n^(2*n^2 - 2*n - 3/2) / exp(3*n^2 - Pi*n*(n+1)/4 - 2*n), where c = 0.07463795295314976973866568785704370572893158254239607676544741150586459722... - _Vaclav Kotesovec_, Nov 25 2023
%t A203675 f[j_] := j^2; z = 12;
%t A203675 u[n_] := Product[f[j]^2 - f[j] f[k] + f[k]^2, {j, 1, k - 1}]
%t A203675 v[n_] := Product[u[n], {k, 2, n}]
%t A203675 Table[v[n], {n, 1, z}] (* A203675 *)
%t A203675 Table[v[n + 1]/v[n], {n, 1, z}] (* A203676 *)
%Y A203675 Cf. A203673, A367668.
%K A203675 nonn
%O A203675 1,2
%A A203675 _Clark Kimberling_, Jan 04 2012