Counting permutations by their alternating runs.

E. Rodney Canfield Herbert S. Wilf Counting permutations by their alternating runs. 213-225 2008 115 J. Comb. Theory, Ser. A 2 http://dx.doi.org/10.1016/j.jcta.2007.05.006 db/journals/jct/jcta115.html#CanfieldW08