A046470 Even numbers with an odd number of prime factors (counted with multiplicity).

2, 8, 12, 18, 20, 28, 30, 32, 42, 44, 48, 50, 52, 66, 68, 70, 72, 76, 78, 80, 92, 98, 102, 108, 110, 112, 114, 116, 120, 124, 128, 130, 138, 148, 154, 162, 164, 168, 170, 172, 174, 176, 180, 182, 186, 188, 190, 192, 200, 208, 212, 222, 230, 236, 238, 242, 244

Offset: 1

Author

Shyam Sunder Gupta, Feb 16 2002

Keywords

• nonn

Examples

			a(2)=8, which is even with odd number of prime factors i.e. 3.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A046337. Intersection of A005843 and A026424.

Programs

Maple

filter:= proc(n) numtheory:-bigomega(n) mod 2 = 1 end proc:
select(filter, [seq(i,i=2..1000,2)]); # Robert Israel, Apr 02 2025

Mathematica

Select[Range[2, 244, 2], OddQ[PrimeOmega[#]] &] (* Jayanta Basu, Jun 26 2013 *)