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%I #8 Dec 27 2013 12:08:35
%S 4,8,9,16,18,25,27,32,36,49,50,54,64,72,75,81,98,99,100,108,121,125,
%T 128,144,147,150,162,169,175,196,198,200,207,216,225,242,243,245,250,
%U 256,288,289,294,297,300,324,338,343,350,361,363,375,392,396,400,414
%N Numbers n such that rad(phi(n)) > phi(rad(n)), where rad(n) is the squarefree kernel of n, and phi is Euler's totient function.
%H Charles R Greathouse IV, <a href="/A226385/b226385.txt">Table of n, a(n) for n = 1..10000</a>
%t rad[n_] := Product[fa[n][[i, 1]], {i,Length[fa[n]]}]; fa = FactorInteger; Select[Range[500], rad[EulerPhi[#]] > EulerPhi[rad[#]] &]
%o (PARI) rad(n)=my(f=factor(n)[,1]); prod(i=1,#f,f[i])
%o is(n)=rad(eulerphi(n))>eulerphi(rad(n)) \\ _Charles R Greathouse IV_, Dec 27 2013
%Y Cf. A007947, A000010, A226384, A226386.
%K nonn
%O 1,1
%A _José María Grau Ribas_, Jun 05 2013
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