OFFSET
1,2
COMMENTS
Sequence contains the numbers 2^(k+1), 2^k*3^(k+1) and 25*10^k, for k > 0.
a(226) > 10^18.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..225
EXAMPLE
m = 178726991395974 = 2*3*7^2*883^4 and phi(m) = 2^3*3^3*7^3*883^3.
MATHEMATICA
Select[Range[10^5], # == 1 || IntegerQ @ Log[Times @@ First /@ FactorInteger @ #, EulerPhi @ #] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Resta, Feb 10 2013
STATUS
approved