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 A323540 #18 Sep 08 2022 08:46:23
%S A323540 0,1,32,2025,204800,30525625,6307891200,1727713080625,606076928000000,
%T A323540 265058191985900625,141409376995328000000,90403125002859606705625,
%U A323540 68229510086445571768320000,60026603304487418050791015625,60893916244529680380723200000000
%N A323540 a(n) = Product_{k=0..n} (k^2 + (n-k)^2).
%H A323540 Seiichi Manyama, <a href="/A323540/b323540.txt">Table of n, a(n) for n = 0..221</a>
%F A323540 a(n) ~ exp((Pi-4)*n/2) * n^(2*n+2).
%t A323540 Table[Product[k^2+(n-k)^2, {k, 0, n}], {n, 0, 20}]
%o A323540 (PARI) m=2; vector(20, n, n--; prod(k=0,n, k^m + (n-k)^m)) \\ _G. C. Greubel_, Jan 18 2019
%o A323540 (Magma) m:=2; [(&*[k^m + (n-k)^m: k in [0..n]]): n in [0..20]]; // _G. C. Greubel_, Jan 18 2019
%o A323540 (Sage) m=2; [product(k^m +(n-k)^m for k in (0..n)) for n in (0..20)] # _G. C. Greubel_, Jan 18 2019
%Y A323540 Cf. A272244, A323425, A323541, A323542, A323543, A323544, A323545, A323546.
%Y A323540 Cf. 2*A000330 and A006331 (with sum instead of product).
%K A323540 nonn
%O A323540 0,3
%A A323540 _Vaclav Kotesovec_, Jan 17 2019