2021 USMCA National Championship #14
Source:
May 9, 2021
Problem Statement
Derek the Dolphin and Kevin the Frog are playing a game where they take turns taking coins from a stack of coins, except with one rule: The number of coins someone takes each turn must be a power of . The person who cannot take any more coins loses. If Derek goes first, how many integers from to inclusive will guarantee him a win? (Example: If , then a possible sequence of turns is: Derek takes one coin, Kevin takes coins, and Kevin wins.)