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

%I #7 Nov 18 2018 09:10:25

%S 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,

%T 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,

%U 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

%N Number of distinct prime factors of numbers that are not prime powers.

%H Harvey P. Dale, <a href="/A074594/b074594.txt">Table of n, a(n) for n = 1..1000</a>

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

%t PrimeNu/@Select[Range[2,300],!PrimePowerQ[#]&] (* _Harvey P. Dale_, Nov 18 2018 *)

%Y Cf. A074595, A074592, A074593.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Aug 25 2002

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