M_{23}

M_{22}  23  1a + 22a  2

Character Numbers: [ 1, 2 ]

\begin{aligned}& S_{1} & S_{2} \\ χ_{1} & 1 & 22 \\ χ_{2} & 1 & −1 \end{aligned}

Ramanujan Graphs: [ 1, 2 ], [ 2 ]