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

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, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73

Offset: 1

Author

Michael B. Porter, Oct 20 2009

Keywords

• easy
• nonn

Comments

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

Examples

			50 = 2*5*5 is in the sequence since it has 3 prime factors and 3 <= 5
64 = 2*2*2*2*2*2 is not in the sequence since it has 6 prime factors
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A046305, A001222

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

Programs

Mathematica

Select[Range[100],PrimeOmega[#]<6&] (* Harvey P. Dale, Jul 13 2011 *)

PARI

isA166719(n) = (bigomega(n) <= 5)