  The discriminator of an integer sequence s = (s(i))_{i>=0}, introduced by
Arnold, Benkoski, and McCabe in 1985, is the function D_s(n) that sends n to
the least integer m such that the numbers s(0), s(1), ..., s(n-1) are pairwise
incongruent modulo m. In this note we present a class of exponential sequences
that have the special property that their discriminators are shift-invariant,
i.e., that the discriminator of the sequence is the same even if the sequence
is shifted by any positive constant.
