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 A255526 #13 Oct 03 2023 03:28:01
%S A255526 -1,1,-4,17,-56,172,-547,1809,-6061,20316,-68135,229244,-774372,
%T A255526 2624119,-8912759,30328593,-103382254,352975681,-1206921212,
%U A255526 4132159452,-14163858895,48601267199,-166930975524,573872089212,-1974472043081,6798561779868,-23425506369715
%N A255526 Coefficient of x^n in Product_{k>=1} 1/(1+x^k)^n.
%H A255526 Vaclav Kotesovec, <a href="/A255526/b255526.txt">Table of n, a(n) for n = 1..500</a>
%F A255526 a(n) ~ (-1)^n * c * d^n / sqrt(n), where d = A318204 = 3.5097543279497033404372735..., c = 0.23322106096789389697797... .
%t A255526 Table[SeriesCoefficient[Product[1/(1+x^k)^n,{k,1,n}],{x,0,n}],{n,1,30}]
%t A255526 (* Calculation of constant c: *) 1/Sqrt[(4 - r^2*s^3*Derivative[0, 2][QPochhammer][-1, r*s])*Pi] /. FindRoot[{QPochhammer[-1, r*s] == 2/s, 2/s + r*s*Derivative[0, 1][QPochhammer][-1, r*s] == 0}, {r, -1/3}, {s, 2}, WorkingPrecision -> 120] (* _Vaclav Kotesovec_, Oct 03 2023 *)
%Y A255526 Cf. A008485, A270913, A278428.
%K A255526 sign
%O A255526 1,3
%A A255526 _Vaclav Kotesovec_, Feb 24 2015