The Cossidente-Penttila graphs are a family of strongly regular graphs constructed by Cossidente and Penttila (2005), with parameters
for 
an odd prime power. For each such 
, the points of the 
-generalized quadrangle 
can be partitioned into two parts such that the
induced subgraph of its point
graph on either part has these parameters.
The admissible values of 
begin 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 27, 29, 31, 37,
41, ... (OEIS A061345, with the initial 1 omitted).
The smallest Cossidente-Penttila graph corresponds to 
and is isomorphic to
the Gewirtz graph.
