2011 ToT Fall Junior A p1 sequence of positive integers, divisors related
Source:
March 22, 2020
divisornumber theory
Problem Statement
An integer is written on the board. Alex writes a sequence of positive integers, obtaining new integers in the following manner: he takes any divisor greater than of the last number and either adds it to, or subtracts it from the number itself. Is it always (for all ) possible for Alex to write the number at some point?