MathDB
PAMO 2016 Q2

Source: PAMO 2016

April 29, 2016
combinatorics

Problem Statement

We have a pile of 20162016 cards and a hat. We take out one card, put it in the hat and then divide the remaining cards into two arbitrary non empty piles. In the next step, we choose one of the two piles, we move one card from this pile to the hat and then divide this pile into two arbitrary non empty piles. This procedure is repeated several times : in the kk-th step (k>1)(k>1) we move one card from one of the piles existing after the step (kāˆ’1)(k-1) to the hat and then divide this pile into two non empty piles. Is it possible that after some number of steps we get all piles containing three cards each?