The Hall-Janko graph, also known as the Hall-Janko-Wales graph, is a strongly regular graph on 100 nodes with parameters . It is also a distance-regular graph with intersection array . It is illustrated above in an embedding due to C. Rocchini.
It is an integral graph with graph spectrum . The Hall-Janko graph has independence number 10 and chromatic number 10, while the graph complement of the Hall-Janko graph has independence number 4 and chromatic number 25 (Brouwer).