Permutations can be considered as the orbits of a dynamic system p' = succ(p), where p is a permutation and p' is its successor in the lexycographically ordered set of permutations (+ Nil) This functions produces those orbits as well as a number of "permutation numbers" derived from those orbits.
More information can be found in the articles "A Formal Model and an Algorithm for Generating the Permutations of a Multiset," WSEAS Transactions on Systems, Vol. 1, No. 1, available at https://goo.gl/zaatLv, and "Permutation Numbers," Complex Systems, Vol. 15, Issue 2, available at https://goo.gl/Tefm8j.