Enumeration of words by the sum of differences between adjacent letters
Toufik Mansour
Abstract
We consider the sum $u$ of differences between adjacent letters
of a word of $n$ letters, chosen uniformly at random from a given alphabet.
This paper obtains the enumerating generating function for the number of such
words with respect to the sum $u$, as well as explicit formulas
for the mean and variance of $u$.
Full Text: PDF PostScript