A Le Monde mathematical puzzle in combinatorics: Given a permutation σ of {1,…,5}, if σ(1)=n, the n first values of σ are inverted. If the process is iterated until σ(1)=1, does this always happen and if so what is the maximal number of iterations? Solve the same question for the set {1,…,2014}. I ran the following basic R