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 A372832 #11 Jan 27 2025 18:39:07
%S A372832 1,1,1,3,1,3,1,3,4,3,1,11,1,3,4,7,1,11,1,7,4,3,1,25,6,3,4,7,1,61,1,7,
%T A372832 4,3,6,9,1,3,4,39,1,2,1,7,23,3,1,9,8,17,4,7,1,2,6,53,4,3,1,49,1,3,31,
%U A372832 15,6,2,1,7,4,129,1,19,1,3,23,7,8,2,1,83
%N A372832 a(n) is the numerator of Sum_{d|n, d <= sqrt(n)} 1/d.
%H A372832 Antti Karttunen, <a href="/A372832/b372832.txt">Table of n, a(n) for n = 1..20000</a>
%F A372832 Numerators of coefficients in expansion of Sum_{k>=1} x^(k^2) / (k * (1 - x^k)).
%e A372832 1, 1, 1, 3/2, 1, 3/2, 1, 3/2, 4/3, 3/2, 1, 11/6, 1, 3/2, 4/3, 7/4, 1, 11/6, ...
%t A372832 nmax = 80; CoefficientList[Series[Sum[x^(k^2)/(k (1 - x^k)), {k, 1, nmax}], {x, 0, nmax}], x] // Numerator // Rest
%o A372832 (PARI) a(n) = numerator(sumdiv(n, d, if (d^2 <= n, 1/d))); \\ _Michel Marcus_, May 14 2024
%Y A372832 Cf. A017665, A066839, A372833 (denominators).
%K A372832 nonn,frac
%O A372832 1,4
%A A372832 _Ilya Gutkovskiy_, May 14 2024