MathDB
Problem 6 of Third round

Source: XI International Festival of Young Mathematicians Sozopol 2022, Theme for 11-12 grade

September 9, 2022
combinatorics

Problem Statement

A mixing of the sequence a1,a2,,a3na_1,a_2,\dots ,a_{3n} is called the following sequence: a3,a6,,a3n,a2,a5,,a3n1,a1,a4,,a3n2a_3,a_6,\dots ,a_{3n},a_2,a_5,\dots ,a_{3n-1},a_1,a_4,\dots ,a_{3n-2}. Is it possible after finite amount of mixings to reach the sequence 192,191,,1192,191,\dots ,1 from 1,2,,1921,2,\dots ,192?