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A074594 Number of distinct prime factors of numbers that are not prime powers. 4
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

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Last modified November 20 17:09 EST 2019. Contains 329337 sequences. (Running on oeis4.)