problem of grasshopper leaping
Source: China south east mathematical olympiad 2012 day2 problem 8
July 17, 2013
combinatorics unsolvedcombinatorics
Problem Statement
Let positive integers satisfy . is a set that contains points on an axis. A grasshopper on the axis can leap from one point to another adjacent point. Find the maximal value of satisfying following conditions:
(a) are two arbitrary points in ;
(b) starting at point , the grasshopper leaps times and finishes at point ; (the grasshopper is allowed to travel and more than once)
(c) there are even number ways for the grasshopper to do (b).