OFFSET
1,2
EXAMPLE
6 is not in the sequence because 6 has four divisors: 1, 2, 3, 6.
MATHEMATICA
Select[Range[100], DivisorSigma[0, #]!=4&] (* Harvey P. Dale, Jan 07 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Aug 11 2012
STATUS
approved