The Robertson graph is the unique -cage graph, illustrated
above. It has 19 vertices and 38 edges. It has girth 5, diameter 3, chromatic
number 3, and is a quartic graph.
The Robertson graph has automorphism group order 24, possesses 5376 (directed) Hamiltonian cycles, and has 224 distinct order-1
generalized LCF notations (with none of higher order).