MathDB

Iran TST 2009-Day4-P3

Source:

May 17, 2009

logarithmsLaTeXcombinatorics proposedcombinatorics

Problem Statement

T

is a subset of

{1,2,...,n}

which has this property : for all distinct

i,j \in T

2j

is not divisible by

i

. Prove that :

|T| \leq \frac {4}{9}n + \log_2 n + 2