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 A373032 #5 May 21 2024 05:30:41
%S A373032 0,1,1,1,1,-3,1,-3,1,-3,1,6,1,-3,10,-3,1,6,1,-19,10,-3,1,-10,1,-3,10,
%T A373032 -19,1,31,1,-19,10,-3,26,-10,1,-3,10,6,1,-30,1,-19,35,-3,1,-46,1,22,
%U A373032 10,-19,1,-30,26,30,10,-3,1,-21,1,-3,59,-19,26,-30,1,-19,10,71
%N A373032 Expansion of Sum_{k>=1} (-1)^(k+1) * k^2 * x^(k*(k+1)) / (1 - x^k).
%F A373032 a(n) = Sum_{d|n, d < sqrt(n)} (-1)^(d+1) * d^2.
%t A373032 nmax = 70; CoefficientList[Series[Sum[(-1)^(k + 1) k^2 x^(k (k + 1))/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] // Rest
%Y A373032 Cf. A056924, A064027, A070039, A321543, A333809, A333810, A339353, A344300, A372625, A373031.
%K A373032 sign
%O A373032 1,6
%A A373032 _Ilya Gutkovskiy_, May 20 2024