... correspondingcanonical sequences. The set of all partitions of [n] with exactly k blocks will be denoted by P (n, k) and has cardinality given by the Stirling number o f the second kind, denoted by Sn,k.Fo r positive ... #R39.[7] M. K la zar, On abab-free and abba-free set part itio ns, Europ. J. Combin. 17 (1996)53–68.[8] T. Mansour and A. Munagi, Enumeration of partitions by long rises, levels anddescents, J. Integer ... alphabet [i], we havethat the generating function Fτ(x, y, k) is given by xkka=1Aa1−xAa, which completes theproof. By way of example, Theorem 2.13 for τ = 312 implies that the generating...