%I #11 Jul 29 2017 19:11:01
%S 1,2,3,6,14,15,30,35,42,70,78,105,190,210,357,418,570,714,910,1045,
%T 1254,2090,2730,3135,4522,4674,5278,6270,10659,12441,13566,14630,
%U 15834,16770,20026,21318,23374,24871,24882,24969,25070,25714,27170,29029
%N Squarefree balanced numbers (i.e., squarefree members of A020492).
%H Donovan Johnson, <a href="/A078557/b078557.txt">Table of n, a(n) for n = 1..10000</a>
%e 210 = 2*3*5*7, sigma(210) = 576, phi(210) = 48, 576/48 = 12.
%t Do[s=DivisorSigma[1, n]/EulerPhi[n]; If[IntegerQ[s]&&!Equal[MoebiusMu[n], 0], k=k+1; Print[n]], {n, 1, 2100000}]
%Y Cf. A020492.
%K nonn
%O 1,2
%A _Labos Elemer_, Dec 06 2002
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