This is an antipodal 3-cover of the Brouwer–Haemers graph, and an induced subgraph of Soicher's second graph.
Number of vertices: | $243$ |
Diameter: | $4$ |
Intersection array: | $\{20,18,4,1;1,2,18,20\}$ |
Spectrum: | $20^1 5^{72} 2^{60} (-4)^{90} (-7)^{20}$ |
Automorphism group: | $3^5:(2\times M_{10})$ |
Distance-transitive: | Yes |
Antipodal |