OFFSET
0,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 0..1000
EXAMPLE
For n={3,11,29}, phi(n)={2,10,28}, d(phi(n))={2,4,6}, d(n)=2, quotient={1,2,3}.
MATHEMATICA
Select[Range@ 132, Mod @@ DivisorSigma[0, {EulerPhi@ #, #}] == 0 &] (* Michael De Vlieger, Jun 29 2018 *)
PROG
(PARI) select(m->frac(numdiv(eulerphi(m))/numdiv(m)) == 0, [1..500]) \\ Harry J. Smith, Aug 11 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 20 2001
EXTENSIONS
Incorrect formula deleted by Jon E. Schoenfield, Jul 02 2018
STATUS
approved