There exist precisely five rank-3 strongly regular graphs on 961 vertices. They are $H(2,31)$, the Paley graph $P_{961}$, the Peisert graph on 961 vertices, and the two graphs below.
Number of vertices: | $961$ |
Diameter: | $2$ |
Intersection array: | $\{240,168;1,56\}$ |
Spectrum: | $240^1 23^{240} (-8)^{720}$ |
Automorphism group: | $31^2:\left(15 \times \left(\mathrm{SL}(2,3).2\right)\right)$ |
Distance-transitive: | Yes |
Primitive |
Number of vertices: | $961$ |
Diameter: | $2$ |
Intersection array: | $\{360,220;1,132\}$ |
Spectrum: | $360^1 19^{360} (-12)^{600}$ |
Automorphism group: | $31^2:\left(15 \times 2.\mathrm{A}_5\right)$ |
Distance-transitive: | Yes |
Primitive |