English

Restricted 132-alternating permutations and Chebyshev polynomials

Combinatorics 2007-05-23 v1

Abstract

A permutation is said to be \emph{alternating} if it starts with rise and then descents and rises come in turn. In this paper we study the generating function for the number of alternating permutations on nn letters that avoid or contain exactly once 132 and also avoid or contain exactly once an arbitrary pattern on kk letters. In several interesting cases the generating function depends only on kk and is expressed via Chebyshev polynomials of the second kind.

Keywords

Cite

@article{arxiv.math/0210058,
  title  = {Restricted 132-alternating permutations and Chebyshev polynomials},
  author = {T. Mansour},
  journal= {arXiv preprint arXiv:math/0210058},
  year   = {2007}
}

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22 pages