A100367 Even numbers with two prime factors, not counting multiplicity.

6, 10, 12, 14, 18, 20, 22, 24, 26, 28, 34, 36, 38, 40, 44, 46, 48, 50, 52, 54, 56, 58, 62, 68, 72, 74, 76, 80, 82, 86, 88, 92, 94, 96, 98, 100, 104, 106, 108, 112, 116, 118, 122, 124, 134, 136, 142, 144, 146, 148, 152, 158, 160, 162, 164, 166, 172, 176, 178, 184, 188

Offset: 1

Author

Labos Elemer, Nov 22 2004

Keywords

• nonn

Comments

This is a proper subset of A098902. E.g., 210 is not here, but it is there.

Numbers of the form 2^k*p^h where k > 0, h > 0, and p is an odd prime. [corrected by Lei Zhou, Oct 29 2018]

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001221.

Intersection of A007774 and A098902.

The even terms of A336101.

A100368 is a subsequence.

Programs

Mathematica

Select[Range[2, 200, 2], PrimeNu@ # == 2 &] (* Michael De Vlieger, Oct 31 2018 *)

PARI

isok(n) = !(n%2) && (omega(n) == 2); \\ Michel Marcus, Feb 02 2018