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A166719 Numbers with at most 5 prime factors (counted with multiplicity) 2

%I #11 May 25 2016 04:52:11

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,

%T 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,

%U 50,51,52,53,54,55,56,57,58,59,60,61,62,63,65,66,67,68,69,70,71,72,73

%N Numbers with at most 5 prime factors (counted with multiplicity)

%C Complement of A046305, A001222(a(n))<=5

%H G. C. Greubel, <a href="/A166719/b166719.txt">Table of n, a(n) for n = 1..10000</a>

%e 50 = 2*5*5 is in the sequence since it has 3 prime factors and 3 <= 5

%e 64 = 2*2*2*2*2*2 is not in the sequence since it has 6 prime factors

%t Select[Range[100],PrimeOmega[#]<6&] (* _Harvey P. Dale_, Jul 13 2011 *)

%o (PARI) isA166719(n) = (bigomega(n) <= 5)

%Y Cf. A046305, A001222

%Y For numbers with at most n prime factors: n=1: A000040, n=2: A037143, n=3: A037144, n=4: A166718.

%K easy,nonn

%O 1,2

%A _Michael B. Porter_, Oct 20 2009

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Last modified March 28 07:33 EDT 2024. Contains 371235 sequences. (Running on oeis4.)