OFFSET
1,30
COMMENTS
Prime factors counted without multiplicity. - Harvey P. Dale, Mar 03 2016
The first term with an absolute value greater than 2 is a(211); the first term with an absolute value greater than 3 is a(2311); the first term with an absolute value greater than 4 is a(43891). - Harvey P. Dale, Mar 03 2016
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
EXAMPLE
For n=105, phi(n)=48, with 3 or 2 prime factors respectively, so a(105) = 3 - 2 = 1.
MATHEMATICA
Table[PrimeNu[n]-PrimeNu[EulerPhi[n]], {n, 90}] (* Harvey P. Dale, Mar 03 2016 *)
PROG
(PARI) for(n=1, 50, print1(omega(n) - omega(eulerphi(n)), ", ")) \\ G. C. Greubel, May 19 2017
CROSSREFS
KEYWORD
sign
AUTHOR
Labos Elemer, Jul 11 2000
STATUS
approved