I found it In Exercise in abstract algebra by Dummit and Foote.
Let $P$ be a Sylow $p$-group of $S_p$.
What is the order of $N_{S_p}(P)$?
I found it In Exercise in abstract algebra by Dummit and Foote.
Let $P$ be a Sylow $p$-group of $S_p$.
What is the order of $N_{S_p}(P)$?
Copyright © 2021 JogjaFile Inc.
If $\;n_p\;$ denotes the number of Syloy $\;p\,-$ subgroups, then we know that
$$n_p=[S_p:N_G(P)]=\frac{p!}{|N_G(P)|}$$
and we know that $\;n_p=(p-2)!\;$