OFFSET
1,1
MATHEMATICA
Select[Range[260000], EulerPhi[DivisorSigma[1, #]]==5*EulerPhi[#]&] (* Harvey P. Dale, Jul 11 2018 *)
PROG
(PARI) isok(n) = eulerphi(sigma(n)) == 5*eulerphi(n); \\ Michel Marcus, Nov 22 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Feb 05 2002
EXTENSIONS
More terms from Michel Marcus, Nov 22 2013
STATUS
approved