A permutation of the integers from 1 to n contains a swap if there exist distinct integers i and j between 1 and n such that i appears at the jth position and j appears in the ith postion (the positions in the permutation are numbered from 1 to n). Find the number of permutations of 1 to n which do not contain a swap.
If the solution is SW(n), post the value of SW(17).
Eg: SW(1)=1, SW(2)=1, SW(3)=3, SW(4)=15, SW(5)=75.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment