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 A099377 #22 Feb 16 2025 08:32:55
%S A099377 1,4,3,12,5,2,7,32,27,20,11,18,13,7,5,80,17,36,19,20,21,22,23,16,75,
%T A099377 52,27,3,29,10,31,64,11,68,35,324,37,38,39,32,41,7,43,22,45,23,47,120,
%U A099377 49,100,17,156,53,18,55,56,57,116,59,30,61,31,189,448,65,11,67,68,23,35
%N A099377 Numerators of the harmonic means of the divisors of the positive integers.
%H A099377 Ivan Neretin, <a href="/A099377/b099377.txt">Table of n, a(n) for n = 1..10000</a>
%H A099377 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OresConjecture.html">Ore's Conjecture</a>
%e A099377 1, 4/3, 3/2, 12/7, 5/3, 2, 7/4, 32/15, ...
%t A099377 f[n_] := DivisorSigma[0, n]/Plus @@ (1/Divisors@n); Numerator@ Array[f, 70] (* _Robert G. Wilson v_, Aug 04 2010 *)
%t A099377 Table[Numerator[DivisorSigma[0, n]/DivisorSigma[-1, n]], {n, 70}] (* _Ivan Neretin_, Nov 13 2016 *)
%o A099377 (PARI) a(n) = my(d=divisors(n)); numerator(#d/sum(k=1, #d, 1/d[k])); \\ _Michel Marcus_, Nov 13 2016
%o A099377 (Python)
%o A099377 from sympy import gcd, divisor_sigma
%o A099377 def A099377(n): return (lambda x, y: y*n//gcd(x,y*n))(divisor_sigma(n),divisor_sigma(n,0)) # _Chai Wah Wu_, Oct 20 2021
%Y A099377 Cf. A099378.
%K A099377 nonn,frac
%O A099377 1,2
%A A099377 _Eric W. Weisstein_, Oct 13 2004
%E A099377 More terms from _Robert G. Wilson v_, Aug 04 2010