4X4 square grid graph coloring a rectangular array: number of n X n 0..15 arrays where 0..15 label nodes of the square grid graph and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.

A223394

4X4 square grid graph coloring a rectangular array: number of n X n 0..15 arrays where 0..15 label nodes of the square grid graph and every array movement to a horizontal or vertical neighbor moves along an edge of this graph.