whoever makes the gcd loses
Source: 239 2015 J6
May 15, 2020
combinatoricsgamegame strategynumber theory
Problem Statement
The numbers are written on the board. Patya and Vassya are playing a game. They take turn alternatively erasing a number from the board. Patya begins. If after a turn all numbers (maybe one) on the board be divisible by a natural number greater than the player who last played loses. If after some number of steps the only remaining number on the board be then they call it a draw. Determine the result of the game if they both play their best.