MathDB
Sequence and inequality

Source: Baltic Way 2016, Problem 10

November 5, 2016
algebra

Problem Statement

Let a0,1,a0,2,...,a0,2016a_{0,1}, a_{0,2}, . . . , a_{0, 2016} be positive real numbers. For n0n\geq 0 and 1k<20161 \leq k < 2016 set an+1,k=an,k+12an,k+1  and  an+1,2016=an,2016+12an,1.a_{n+1,k} = a_{n,k} +\frac{1}{2a_{n,k+1}} \ \ \text{and} \ \ a_{n+1,2016} = a_{n,2016} +\frac{1}{2a_{n,1}}. Show that max1k2016a2016,k>44.\max_{1\leq k \leq 2016} a_{2016,k} > 44.