OFFSET
1,2
FORMULA
EXAMPLE
a(10) = 7; There are 7 numbers less than or equal to 10 that are either squarefree, a divisor of 10, or both. The numbers are 1,2,3,5,6,7,10.
MATHEMATICA
Module[{nn=80, sf}, sf=Select[Range[nn], SquareFreeQ[#]&]; Table[Length[Union[Select[sf, #<= n&], Divisors[n]]], {n, nn}]] (* Harvey P. Dale, Jul 03 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Feb 12 2022
STATUS
approved