Anna and Orjan play a game, writine a pos. integer as sum of 2 others
Source: 2008 Swedish Mathematical Competition p5
April 27, 2021
combinatoricsgamegame strategy
Problem Statement
Anna and Orjan play the following game: they start with a positive integer , Anna writes it as the sum of two other positive integers, . Orjan deletes one of them, or . If the remaining number is larger than , the process is repeated, i.e. Anna writes it as the sum of two positive integers, , Orjan deletes one of them etc. The game ends when the last number is . Orjan is the winner if there are two equal numbers among the numbers he has deleted, otherwise Anna wins. Who is winning the game if n = 2008 and they both play optimally?