Journal of Integer Sequences, Vol. 8 (2005), Article 05.5.6 |
Abstract: We consider an animal S as a set of points in the coordinate plane that are reachable from the origin (0,0) through points in S by steps from {(1,0),(0,1),(1,1),(-1,-1)}. In this paper, we give a combinatorial bijection with 2-Motzkin paths, i.e., the Motzkin paths with two different horizontal steps.
(Concerned with sequence A000108 .)
Received October 2 2005; revised version received November 1 2005. Published in Journal of Integer Sequences November 1 2005.