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
KEYWORD
nonn,easy
AUTHOR
Shyam Sunder Gupta, Oct 14 2004
STATUS
approved