A055743 - OEIS

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A055743

Phi(n) has fewer distinct prime divisors than n.

2, 6, 10, 12, 15, 20, 24, 30, 34, 40, 42, 48, 51, 60, 66, 68, 70, 78, 80, 84, 85, 90, 96, 102, 105, 110, 114, 120, 126, 130, 132, 136, 138, 140, 150, 156, 160, 165, 168, 170, 174, 180, 182, 190, 192, 195, 204, 210, 220, 222, 228, 230, 234, 238, 240, 246, 252

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

n=996 has 3 distinct prime divisors, 2, 3, and 83, while phi(996) = 328 = 2*2*2*41 has only 2 distinct 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