In article <mailman.993.1203474309.9267.python-list at python.org>, Steve Holden <steve at holdenweb.com> wrote: > Of course, but ROT13 ^ (2n*1) is equivalent to ROT13 for all positive > integer n. Why restrict that to positive integers? I believe it works for all integers. But I do think you meant 2n+1, not 2n*1.