Abstract
The excedance set of a permutation π=π1π2···πn is the set of indices i for which πii. We give a formula for the number of permutations with a given excedance set and recursive formulas satisfied by these numbers. We prove log-concavity of certain sequences of these numbers and we show that the most common excedance set among permutations in the symmetric group Sn is 1,2,...,⌊n/2⌋. We also relate certain excedance set numbers to Stirling numbers of the second kind, and others to the Genocchi numbers.
Original language | English |
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Pages (from-to) | 284-299 |
Number of pages | 16 |
Journal | Advances in Applied Mathematics |
Volume | 24 |
Issue number | 3 |
DOIs | |
State | Published - Apr 2000 |
Bibliographical note
Funding Information:The authors thank Margaret Readdy who read an earlier version of this paper. The rst author was in part supported by National Science Foundation, DMS 97-29992, and NEC Research Institute, Inc.
ASJC Scopus subject areas
- Applied Mathematics