A098902 Even numbers whose number of distinct prime factors is also even.

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

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Example

a(3)=12 because 12 is even and number of distinct prime factors of 12 is also even i.e. 2

Mathematica

Select[Range[800], And@@EvenQ[{#, PrimeNu[#]}]&] (* Vincenzo Librandi, Feb 21 2014 *)
Select[Range[0, 200, 2], EvenQ[PrimeNu[#]]&] (* Harvey P. Dale, Apr 06 2018 *)

Crossrefs

Cf. A001221.

Sequence in context: A176552 A176587 A174164 * A100367 A213716 A337486

Adjacent sequences: A098899 A098900 A098901 * A098903 A098904 A098905

Keyword

nonn,easy

Author

Shyam Sunder Gupta, Oct 14 2004

Status

approved