n = a*b , numbers of the form a^b
Source: Azerbaijan NMO 2023. Senior P1
August 24, 2023
number theoryAZE SENIOR NATIONAL MO
Problem Statement
The teacher calculates and writes on the board all the numbers that satisfy the condition for the natural number Here and are natural numbers. Is there a natural number such that each of the numbers is the last digit of one of the numbers written by the teacher on the board? Justify your opinion.