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 A104526 #7 Jun 19 2023 16:52:49
%S A104526 1,4,35,257,11,271,183,2773,36329,109897,110443,27757,55709,37291,
%T A104526 49873,1549703,13975537,14010257,2806565,2811401,5631265,9400487,
%U A104526 103518197,103642321,103738417,311569891,311818139,312084119,312296903,312607213
%N A104526 Numerator of sum(1/(phi(k)sigma(k)),k=1..n), where phi(k) is the totient function and sigma(k) is the sum of the divisors function.
%C A104526 The first 5 sums are: 1,4/3,35/24,257/168,11/7.
%H A104526 Harvey P. Dale, <a href="/A104526/b104526.txt">Table of n, a(n) for n = 1..1000</a>
%e A104526 a(3)=35 because phi(1)*sigma(1)+phi(2)*sigma(2)+phi(3)*sigma(3)=1/(1*1)+1/(1*3)+1/(2*4)=35/24.
%p A104526 with(numtheory): a:=n->numer(sum(1/phi(k)/sigma(k),k=1..n)): seq(a(n),n=1..35);
%t A104526 Accumulate[Table[1/(EulerPhi[n]DivisorSigma[1,n]),{n,30}]]//Numerator (* _Harvey P. Dale_, Jun 19 2023 *)
%Y A104526 Cf. A104527, A093827.
%K A104526 frac,nonn
%O A104526 1,2
%A A104526 _Emeric Deutsch_, Mar 12 2005