Assuming you meant "where
x is any integer":

is defined as

, so it would be defined for every value of

except for those where

, which is true when

and

, where

is some integer. These values of

where

is undefined are both
irrational; they cannot be expressed as a ratio between two integers, and so limiting the domain to integers makes sure that we'll skip over those points every time as

is increasing.
So, the domain of

, when limiting that domain to the integers, is
the set of all integers, 
.