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

1,2

Comments

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

Links

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

Example

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

Mathematica

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

Prog

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

Crossrefs

Cf. A046305, A001222

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

Sequence in context: A146297 A296876 A144972 * A272159 A227981 A085736

Adjacent sequences: A166716 A166717 A166718 * A166720 A166721 A166722

Keyword

easy,nonn

Author

Michael B. Porter, Oct 20 2009

Status

approved