I. This paper investigates the
occurrences of the square-free integers in sequences sn= [f(n)],n = 1,2,8,⋯ where
f(x) belongs to classes of functions described by ‘smoothness’ conditions. The result
obtained is an extention of the well known fact that Q(x) = 6∕π2x + O(X1∕2), where
Q(x) = number of squarefree integers ≦ x; it states that Qs(x) ∼ 6∕π2g(x) where
Q𝜖(x) = number of squarefree integers ≦ x in the sequence sn, and g(x) is the inverse
function of f(x).