This is the first-known example of a strongly regular graph with parameters $(216,40,4,8)$, arising from an imprimitive action of the group $\mathrm{PSU}(4,2)$, discovered by Crnković, Rukavina and Švob (2018). We introduce the name "Rijeka graph" for this graph in honour of their home city.

Number of vertices: | $216$ |

Diameter: | $2$ |

Intersection array: | $\{40,35;1,8\}$ |

Spectrum: | $40^1 4^{140} (-8)^{75}$ |

Automorphism group: | $\mathrm{PSU}(4,2):2$ |

Distance-transitive: | No |

Primitive |

- Adjacency matrix
- Adjacency matrix in GAP format
- Adjacency matrix in CSV format
- Graph in GRAPE format

- D. Crnković, S. Rukavina and A. Švob, New strongly regular graphs from orthogonal groups $O^+(6,2)$ and $O^-(6,2)$,
*Discrete Math.***341**(2018), 2723–2728. - D. Crnković, F. Pavese and A. Švob, On the $PSU(4,2)$-invariant vertex-transitive strongly regular $(216,40,4,8)$ graph,
*Graphs Combin.***36**(2020), 503–513.