Replace both of them by their sum
Source: MEMO 2008, Team, Problem 6
September 10, 2008
algorithmfunctioncombinatorics unsolvedcombinatorics
Problem Statement
On a blackboard there are n \geq 2, n \in \mathbb{Z}^{\plus{}} numbers. In each step we select two numbers from the blackboard and replace both of them by their sum. Determine all numbers for which it is possible to yield identical number after a finite number of steps.