For a positive integer
$r\geq 2$
, a natural number n is r-free if there is no prime p such that
$p^r\mid n$
. Asymptotic formulae for the distribution of r-free integers in the floor function set
$S(x):=\{\lfloor x/ n \rfloor :1\leq n\leq x\}$
are derived. The first formula uses an estimate for elements of
$S(x)$
belonging to arithmetic progressions. The other, more refined, formula makes use of an exponent pair and the Riemann hypothesis.