Let $R$ be a reduced root system, $W$ the associated Weyl group, and $w_0 \in W$ the longest element of $W$. In general $w_0$ admits more than one reduced decomposition into a product of reflections, a number which we denote by $d_R$. Where can one find a list of values of $d_R$ for low-dimensional root systems?

For example are the explicit values of $d_R$ known for the exceptional root systems?

nota product formula (as Stanley mentions there is a big prime, 193, in the factorization of the number of reduced words of the longest word in Type $D_4$). As for exceptionals I don't know of a list but this is in principle something a computer can do. $\endgroup$ – Sam Hopkins Aug 28 at 16:36