English

The number of permutations with a given number of sequences

Combinatorics 2007-05-23 v1

Abstract

P(n,s) denotes the number of permutations of 1,2,...n that have exactly s sequences. Canfield and Wilf [math.CO/0609704] recently showed that P(n,s) can be written as a sum of s polynomials in n. We determine these polynomials explicitly and also obtain explicit expressions for P(n,s) and its fixed-s generating function u_s(x).

Keywords

Cite

@article{arxiv.math/0610462,
  title  = {The number of permutations with a given number of sequences},
  author = {Marcus Kollar},
  journal= {arXiv preprint arXiv:math/0610462},
  year   = {2007}
}

Comments

5 pages