China Mathematics Olympiads (National Round) 2007 Problem 5
Source:
November 28, 2010
algebra unsolvedalgebra
Problem Statement
Let be a bounded sequence satisfying
a_n < \displaystyle\sum_{k=a}^{2n+2006} \frac{a_k}{k+1} + \frac{1}{2n+2007} \forall n = 1, 2, 3, \ldots
Show that
a_n < \frac{1}{n} \forall n = 1, 2, 3, \ldots