标题：Counting occurrences of <mml:math alttext="$132$" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>132</mml:mn></mml:math> in an even permutation
期刊名称：International Journal of Mathematics and Mathematical Sciences
印刷版ISSN：0161-1712
电子版ISSN：1687-0425
出版年度：2004
卷号：2004
DOI：10.1155/S0161171204304114
出版社：Hindawi Publishing Corporation
摘要：We study the generating function for the number of even (or odd)
permutations on n letters containing exactly r≥0 occurrences
of a 132 pattern. It is shown that finding this function for a
given r amounts to a routine check of all permutations in
𝔖2r.
