OFFSET
1,2
EXAMPLE
360 is not in the sequence because it has two possible expressions: 2*3*6*10 or 2*6*30.
MATHEMATICA
nn=300;
sqfacs[n_]:=If[n<=1, {{}}, Join@@Table[Map[Prepend[#, d]&, Select[sqfacs[n/d], Min@@#>d&]], {d, Select[Rest[Divisors[n]], SquareFreeQ]}]];
Select[Range[nn], Length[sqfacs[#]]===1&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 11 2017
STATUS
approved