Patterns and Fractions
Combinatorics
2007-05-23 v1
Abstract
We find, in the form of a continued fraction, the generating function for the number of (132)-avoiding permutations that have a given number of (123) patterns, and show how to extend this to permutations that have exactly one (132) pattern. We find some properties of the continued fraction, which is similar to, though more general than, those that were studied by Ramanujan.
Cite
@article{arxiv.math/9906154,
title = {Patterns and Fractions},
author = {Aaron Robertson and Herb Wilf and Doron Zeilberger},
journal= {arXiv preprint arXiv:math/9906154},
year = {2007}
}
Comments
This paper supercedes "The number of permutations with a prescribed number of 132 and 123 patterns" (math.CO/9903170)