A226385 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.
4, 8, 9, 16, 18, 25, 27, 32, 36, 49, 50, 54, 64, 72, 75, 81, 98, 99, 100, 108, 121, 125, 128, 144, 147, 150, 162, 169, 175, 196, 198, 200, 207, 216, 225, 242, 243, 245, 250, 256, 288, 289, 294, 297, 300, 324, 338, 343, 350, 361, 363, 375, 392, 396, 400, 414
Offset: 1
Keywords
Links
- Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
rad[n_] := Product[fa[n][[i, 1]], {i,Length[fa[n]]}]; fa = FactorInteger; Select[Range[500], rad[EulerPhi[#]] > EulerPhi[rad[#]] &] -
PARI
rad(n)=my(f=factor(n)[,1]); prod(i=1,#f,f[i]) is(n)=rad(eulerphi(n))>eulerphi(rad(n)) \\ Charles R Greathouse IV, Dec 27 2013