> Output can be in any reasonable format, as long as it's clear there are rows and rightly aligned columns: I.e. STDOUT; returning as String with newlines; returning as list of Strings; etc. Your call.
The output may also contain a delimiter of your own choice (except for whitespaces and new-lines): I.e. , and ; and | are all acceptable delimiters.
The output lines may not contain a leading or trailing delimiter.
The output may contain ONE trailing new-line, and any line may contain any number of trailing spaces.
The Challenge
Given the number of items, n, in a non-empty, sorted list output the index, i(n), at which its
"Back-To-Front Permutation"
would reside in a list of all permutations if said permutations were sorted lexicographically.
Results may be 0 or 1-based, just say which (that is i, not n)....
