gen is a utility similar to seq, but for characters. For example:
gen z
prints the alphabet in lower case, all letters from 'a' to 'z', separated by newlines.
gen 17576
prints:
aaa
aab
aac
#[lines cut out]
zzx
zzy
zzz
gen can be used for generating test data or generic filenames.
make install
should install gen to /usr/local if not configured otherwise.