A175786 Numbers n such that the number of prime divisors of n (counted with multiplicity) is not a divisor of phi(n).

8, 12, 20, 30, 32, 44, 48, 50, 54, 64, 66, 68, 72, 75, 80, 81, 92, 96, 102, 108, 110, 112, 116, 120, 125, 128, 138, 160, 162, 164, 165, 168, 170, 174, 180, 188, 192, 208, 212, 230, 236, 240, 242, 243, 246, 252, 255, 270, 272, 275, 280, 282, 284, 288, 290, 304

Offset

1,1

Comments

a(n) is in the sequence if A001222(n) does not divides A000010(n).

Links

Enrique Pérez Herrero, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[2, 400], Mod[EulerPhi[#], PrimeOmega[#]]!=0&] (* Harvey P. Dale, Mar 14 2020 *)

Prog

(PARI) isok(n) =  (eulerphi(n) % bigomega(n)); \\ Michel Marcus, Aug 27 2013

Crossrefs

Cf. A074946, A109421, A109423, A013929.

Sequence in context: A337877 A211410 A001749 * A258848 A072843 A354069

Adjacent sequences: A175783 A175784 A175785 * A175787 A175788 A175789

Keyword

nonn

Author

Enrique Pérez Herrero, Sep 04 2010

Status

approved