jtr or crunch ?? help pls

[davee24]

hi i want to generate password of all uppercase letters A-Z of 8 digits which i can easily do with crunch but i rekon that most passwords would contain no more than 3 instances of the same letter for example ABCDAEFAG would be fine but ABCDAEAGA would not so basically i want to generate 8 digit uppercase A_Z password which contain the same letter no more than 3 time in each password ?? I hope i've explained this ok ?? anyway i presume john would be the logical choice to do this and i've looked a quite a few tut's but i quite new to all this and i cant seem to suss it out can anyone help me pls ????

[bofh28]

# ./crunch 8 8 -f charset.lst ualpha -d 1@
will prevent crunch from doing: aaaaaaaa aaaaaaab aaaaaaac etc
you will get
abababab
abababac
abababad
abababae
abababaf
abababag
abababah
abababai