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 A382958 #12 Apr 25 2025 06:34:24
%S A382958 1,2,30,920,53078,4828892,643086588,117718532696,28378716172822,
%T A382958 8713799596723484,3320414836230009080,1537509304647364575716,
%U A382958 850310874146059999520372,553587598414859641796343780,419087377790397643526857611312,365040505934072220586791778761920
%N A382958 a(n) = (n!)^2 * [(x*y)^n] Product_{k>=1} 1 / (1 - (x^k + y^k)/k!).
%H A382958 Vaclav Kotesovec, <a href="/A382958/b382958.txt">Table of n, a(n) for n = 0..100</a>
%F A382958 a(n) ~ c * sqrt(Pi) * 2^(2*n + 1) * n^(2*n + 1/2) / exp(2*n), where c = Product_{k>=2} (1 + 1/(2^(k-1)*k! - 1)) = 1.399382837233736726730568376611759424994992988... - _Vaclav Kotesovec_, Apr 24 2025
%t A382958 Table[(n!)^2 SeriesCoefficient[Product[1/(1 - (x^k + y^k)/k!), {k, 1, n}], {x, 0, n}, {y, 0, n}], {n, 0, 15}]
%Y A382958 Cf. A005651, A322211.
%K A382958 nonn
%O A382958 0,2
%A A382958 _Ilya Gutkovskiy_, Apr 10 2025