Permutations which are the Union of an Increasing and a Decreasing Subsequence

It is shown that there are 2n n − n−1 m=0 2n−m−1 2m m permutations which are the union of an increasing sequence and a decreasing sequence. 1991 Mathematics Subject Classification 05A15 Submitted: December 1, 1997; Accepted: January 10, 1998

• Type: Journal
• Year: 1998
• Where: COMBINATORICS
• Authors: M. D. Atkinson
• Keywords: COMBINATORICS 1998, Decreasing Sequence, Increasing Sequence, Mathematics Subject Classification