A074594 - OEIS

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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

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

OFFSET

1,1

LINKS

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

FORMULA

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

MATHEMATICA

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

CROSSREFS

Cf. A074595, A074592, A074593.

Sequence in context: A090620 A151659 A057467 * A211667 A001069 A156877

Adjacent sequences: A074591 A074592 A074593 * A074595 A074596 A074597

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Aug 25 2002

STATUS

approved