The Janko-Kharaghani-Tonchev graph is a strongly regular graph on 324 vertices and 24786 edges. It has regular parameters 
.
It is implemented in the Wolfram Language as GraphData["JankoKharaghaniTonchevGraph"].
Janko-Kharaghani-Tonchev Graph
See also
Ionin-Kharaghani Graph, Janko-Kharaghani Graphs, Strongly Regular GraphExplore with Wolfram|Alpha
References
Janko, Z.; Kharaghani, H.; and Tonchev, V. D. "The Existence of a Bush-Type Hadamard Matrix of Order 324 and Two New Infinite Classes of Symmetric Designs." Des. Codes Cryptogr. 24, 225-232, 2001.Cite this as:
Weisstein, Eric W. "Janko-Kharaghani-Tonchev Graph." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Janko-Kharaghani-TonchevGraph.html