Number of possible ball distributions
Source: 2018 JBMO TST - Turkey, P4
March 27, 2020
combinatorics
Problem Statement
boxes are placed around a circle. At the first step we choose some boxes. At the second step for each chosen box we put a ball into the chosen box and into each of its two neighbouring boxes. Find the total number of possible distinct ball distributions which can be obtained in this way. (All balls are identical.)