OFFSET
1,2
EXAMPLE
n=30: phi[30]=8, cototient[30]=22,phi[22]=10 is not a power of 2.
MATHEMATICA
Do[s=EulerPhi[n-EulerPhi[n]]; If[ !IntegerQ[Log[2, s]]&&!PrimeQ[n], Print[n]], {n, 1, 256}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, May 08 2002
STATUS
approved