|
%I #12 Jul 11 2018 12:46:26
%S 336,1008,1680,4368,5040,12432,13104,21840,24528,37296,52752,57792,
%T 62160,64848,65520,73584,93072,105168,122640,128520,133392,141456,
%U 153552,158256,161616,167700,173376,181776,186480,194544,205968,222096,226128,246288,254352
%N Numbers n such that phi(sigma(n)) = 5*phi(n).
%t Select[Range[260000],EulerPhi[DivisorSigma[1,#]]==5*EulerPhi[#]&] (* _Harvey P. Dale_, Jul 11 2018 *)
%o (PARI) isok(n) = eulerphi(sigma(n)) == 5*eulerphi(n); \\ _Michel Marcus_, Nov 22 2013
%Y Cf. A067706.
%K nonn
%O 1,1
%A _Benoit Cloitre_, Feb 05 2002
%E More terms from _Michel Marcus_, Nov 22 2013
|
