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 A304582 #10 Feb 16 2025 08:33:54
%S A304582 1,1,1,2,144,72,64800,1800,2822400,3175200,317520000,635040,
%T A304582 11064936960,15367968,2545242860160,14609174580000,8310997094400,
%U A304582 259718659200,24319016372851200,75058692508800,10838475198270720000,2389883781218693760,374701571140216320
%N A304582 Denominator of Sum_{k=1..n-1} 1/(k*(n-k))^2.
%H A304582 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Dilogarithm.html">Dilogarithm</a>.
%H A304582 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Polylogarithm.html">Polylogarithm</a>.
%e A304582 0, 0, 1, 1/2, 41/144, 13/72, 8009/64800, 161/1800, 190513/2822400, ...
%t A304582 CoefficientList[Series[PolyLog[2, x]^2, {x, 0, 25}], x]//Denominator
%t A304582 Table[Sum[1/(k*(n - k))^2, {k, 1, n - 1}], {n, 0, 25}]//Denominator
%Y A304582 Cf. A002548, A304581, A302827.
%K A304582 nonn,frac
%O A304582 0,4
%A A304582 _Vaclav Kotesovec_, May 15 2018