On the enumeration of restricted words over a finite alphabet

Daniel Birmajer, Juan B. Gil, Michael D. Weiner

Published 2015-09-07Version 1

We present a method for the enumeration of restricted words over a finite alphabet. Restrictions are described through the inclusion or exclusion of suitable building blocks used to construct the words by concatenation. Our approach, which relies on the invert transform and its representation in terms of partial Bell polynomials, allows us to generalize and address in a systematic manner previous results in the subject.