MathDB

Two people,

A

and

B

, play the following game:

A

start choosing a positive integrer number and then, each player in it's turn, say a number due to the following rule: If the last number said was odd, the player add

7

to this number; If the last number said was even, the player divide it by

2

. The winner is the player that repeats the first number said. Find all numbers that

A

can choose in order to win. Justify your answer.

Problem Statement