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 A220345 #10 Sep 06 2019 15:02:08
%S A220345 1,3,4,6,6,12,8,24,12,18,12,48,14,24,48,48,18,36,20,72,64,36,24,192,
%T A220345 30,42,36,96,30,144,32,96,96,54,96,144,38,60,112,288,42,192,44,144,
%U A220345 144,72,48,384,56,90,144,168,54,108,144,384,160,90,60,576,62,96
%N A220345 Ratio of Jordan's totient to Carmichael's lambda function: a(n) = A007434(n) / A002322(n).
%C A220345 a(n) is always integer because lambda(n) divides phi(n), and phi(n) divides J_2(n).
%H A220345 Amiram Eldar, <a href="/A220345/b220345.txt">Table of n, a(n) for n = 1..10000</a>
%F A220345 a(n) = A007434(n) / A002322(n) = A034380(n) * A001615(n).
%t A220345 jordanTotient[n_, k_: 1] := DivisorSum[n, #^k*MoebiusMu[n/#] &] /; (n > 0) && IntegerQ[n]; Table[jordanTotient[n, 2]/CarmichaelLambda[n], {n, 100}] (* _T. D. Noe_, Dec 11 2012 *)
%Y A220345 Cf. A001615, A002322, A007434, A034380.
%K A220345 nonn
%O A220345 1,2
%A A220345 _Enrique Pérez Herrero_, Dec 11 2012