|Journal of Integer Sequences, Vol. 7 (2004), Article 04.1.2|
Abstract: We study the construction of closed meanders and systems of closed meanders, using Motzkin words with four letters. These words are generated by applying binary operation on the set of Dyck words. The procedure is based on the various kinds of intersection of the meandric curve with the horizontal line.
(Concerned with sequences A000108 and A005315 .)
Received April 21 2003; revised version received January 20 2004. Published in Journal of Integer Sequences February 10 2004.