A074594 Number of distinct prime factors of numbers that are not prime powers.

2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 3, 3, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2

Offset: 1

Author

Reinhard Zumkeller, Aug 25 2002

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A074595, A074592, A074593.

Programs

Mathematica

PrimeNu/@Select[Range[2,300],!PrimePowerQ[#]&] (* Harvey P. Dale, Nov 18 2018 *)

Formula

a(n) = A001221(A024619(n)).