A real number
is
-dense if every possible finite string
of consecutive digits occurs in the base-
expansion of
. If
is
-normal, then
is
-dense. If
is
-dense for some
, then
is an irrational number.
Equivalently,
is
-dense
if the sequence of fractional parts
is dense in the unit
interval (Bailey and Crandall 2001, 2002).