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 A364351 #16 Jul 20 2023 10:47:05
%S A364351 1,1,15,-6,40,12,77,-60,180,30,187,-120,260,56,630,-376,442,117,551,
%T A364351 -340,1218,132,805,-1104,1325,182,1998,-672,1276,360,1457,-2032,2970,
%U A364351 306,3290,-1710,2072,380,4134,-3080,2542,672,2795,-1672,7830,552,3337,-6816,4998,775,7038,-2340,4240,1080
%N A364351 Expansion of Sum_{k>0} k^2 * x^k/(1 + x^k)^3.
%H A364351 Seiichi Manyama, <a href="/A364351/b364351.txt">Table of n, a(n) for n = 1..10000</a>
%F A364351 a(n) = (n/2) * Sum_{d|n} (-1)^(n/d+1) * (d+n) = (n/2) * (A000593(n) + n * A048272(n)).
%t A364351 a[n_] := DivisorSum[n, (-1)^(n/#+1) * (#+n) &] * n/2; Array[a, 55] (* _Amiram Eldar_, Jul 20 2023 *)
%o A364351 (PARI) my(N=60, x='x+O('x^N)); Vec(sum(k=1, N, k^2*x^k/(1+x^k)^3))
%Y A364351 Cf. A320900, A364343.
%Y A364351 Cf. A000593, A048272, A309732.
%K A364351 sign
%O A364351 1,3
%A A364351 _Seiichi Manyama_, Jul 19 2023