MathDB
Beautiful subset

Source: Balkan MO 1996, Problem 4

October 29, 2005
combinatorics proposedcombinatorics

Problem Statement

Suppse that X={1,2,,219961}X=\{1,2, \ldots, 2^{1996}-1\}, prove that there exist a subset AA that satisfies these conditions: a) 1A1\in A and 219961A2^{1996}-1\in A; b) Every element of AA except 11 is equal to the sum of two (possibly equal) elements from AA; c) The maximum number of elements of AA is 20122012. Romania