Аннотация:
Koolen and Park classified Shilla graphs with $b=2$ and with $b=3$.
Prime divisors of orders of automorphisms and the fixed
point subgraphs of automorphisms of prime orders are studied for a
hypothetical distance-regular graph $\Gamma$ with intersection array
$\{24,18,9;1,1,16\}$.
Let $G={\rm Aut}(\Gamma)$ is nonsolvable group, $\bar G=G/S(G)$ and $\bar T$
is the socle of $\bar G$. Then $G$ contains now elements of order 35 and
$\bar T\cong J_2, A_{10}$ or $\Omega^+_8(2)$. In particular graph $\Gamma$
is not vertex symmetric.