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 A372836 #11 Jun 10 2024 10:02:46
%S A372836 0,0,0,1,0,5,0,3,1,7,0,5,0,9,8,7,0,10,0,21,10,13,0,35,1,15,4,27,0,41,
%T A372836 0,15,14,19,12,3,0,21,16,49,0,53,0,39,32,25,0,25,1,21,20,45,0,65,16,9,
%U A372836 22,31,0,107,0,33,40,31,18,7,0,57,26,73,0,61,0,39,16,63,18,89,0,21
%N A372836 a(n) is the numerator of Sum_{d|n, 1 < d < n} 1/d.
%H A372836 Antti Karttunen, <a href="/A372836/b372836.txt">Table of n, a(n) for n = 1..16384</a>
%F A372836 Numerators of coefficients in expansion of Sum_{k>=2} x^(2*k) / (k * (1 - x^k)).
%e A372836 0, 0, 0, 1/2, 0, 5/6, 0, 3/4, 1/3, 7/10, 0, 5/4, 0, 9/14, 8/15, 7/8, 0, 10/9, ...
%t A372836 nmax = 80; CoefficientList[Series[Sum[x^(2 k)/(k (1 - x^k)), {k, 2, nmax}], {x, 0, nmax}], x] // Numerator // Rest
%o A372836 (PARI) a(n) = numerator(sumdiv(n, d, if ((d>1) && (d<n), 1/d))); \\ _Michel Marcus_, May 14 2024
%Y A372836 Cf. A017665, A048050, A277790, A277791.
%K A372836 nonn,frac
%O A372836 1,6
%A A372836 _Ilya Gutkovskiy_, May 14 2024