A graph G having chromatic number χ(G)<=k is called a k-colorable graph. In contrast, a graph having χ(G) = k is said to be a k-chromatic graph. Note that k-colorable graphs are related but distinct from k-colored graphs. The 1, 2, 3, and 7, and 13 distinct simple 2-colorable graphs on n = 1, ..., 5 nodes are illustrated above. The 1, 2, 4, and 10, and 29 distinct simple 3-colorable graphs on n = 1, ..., 5 nodes are illustrated above. The 1, 2, 4, and 11, and 33 distinct simple 4-colorable graphs on n = 1, ..., 5 nodes are illustrated above.