Armand who are you to be so rude to Jethro no offence but Jethro is one of the best coders i know and for this /rnick rubbish you can just use.
alias rnick { .set %a $nick(#,0)
.set %b $rand(1,%a)
.echo -a $nick(#,%b)
or use
.echo -a $nick(#,$rand(1,$nick(#,0)))
simple, oh and Jethro_'s information is correct.