Combinatorica`
Combinatorica`
UnrankPermutation
UnrankPermutation[r,l]
gives the 
permutation in the lexicographic list of permutations of list 
.
UnrankPermutation[r,n]
gives the 
permutation in the lexicographic list of permutations of 
.
Details and Options
- To use UnrankPermutation, you first need to load the Combinatorica Package using Needs["Combinatorica`"].