Sure seq is OK, but jot does everything seq does and more, so I prefer jot.
# generate 10 random numbers between 1 and 1 million
jot -r 10 1 1000000
I meant to go all "just use coreutils, there is shuf available already, no need for some third-party tool" but then I realised that jot is an integral part of BSD. Rock on! :)