A path composed of connected horizontal and vertical line segments, each passing between adjacent Lattice Points. A lattice path is therefore a Sequence of points , , ..., with such that each is a Lattice Point and is obtained by offsetting one unit east (or west) or one unit north (or south).

The number of paths of length from the Origin (0,0) to a point which are restricted to east and north steps is given by the Binomial Coefficient .

**References**

Dickau, R. M. ``Shortest-Path Diagrams.'' http://forum.swarthmore.edu/advanced/robertd/manhattan.html.

Hilton, P. and Pederson, J. ``Catalan Numbers, Their Generalization, and Their Uses.'' *Math. Intel.* **13**, 64-75, 1991.

© 1996-9

1999-05-26