IMO 1986 LL FRG27
In an urn there are n balls numbered 1, 2, . . . , n. They are
IMO 1986 LL FRG27
Origin: FRG
Problem
In an urn there are n balls numbered 1, 2, . . . , n. They are drawn at random one by one one without replacement and the numbers are recorded. What is the probability that the resulting random permutation has only one local maximum? A term in a sequence is a local maximum if it is greater than all its neighbors.