OFFSET
1,1
COMMENTS
Conjecture: a(n) ~ n. - Charles R Greathouse IV, Mar 04 2017
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
All primes except Fermat primes are included. Also proper prime powers are included, such as 289 because phi(289) = 17*16 = 272 with 2 prime divisors. Besides many composites are included like 998 = 2*499 because phi(998) = 498 = 2*3*83 with 3 > 2 prime factors.
MATHEMATICA
Select[Range[100], PrimeNu[EulerPhi[#]] > PrimeNu[#] &] (* G. C. Greubel, May 13 2017 *)
PROG
(PARI) is(n)=my(f=factor(n)); omega(eulerphi(f)) > #f~ \\ Charles R Greathouse IV, Mar 04 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 11 2000
STATUS
approved