Monthly Archives: June 2014

Yet Another Nice Proof of the Derangements Formula

A couple of posts from a few years back give proofs of the formula for , the number of derangements on n elements.  (A derangement is a permutation with no fixed points.)  Both proofs avoid the use of the principle of inclusion-exclusion, which … Continue reading

Posted in combinatorics, derangements, permutations | Leave a comment