MathDB
0s and 1s in rectangular board

Source: Argentina 2004 OMA L3 p3

May 12, 2024
combinatorics

Problem Statement

Zeros and ones are placed in each square of a rectangular board. Such a board is said to be varied if each row contains at least one 00 and at least two 11s. Given n3,\geq 3, find all integers k>1k>1 with the following property:
The columns of each varied board of kk rows and n columns can be permuted so that in each row of the new board the 11s do not form a block (that is, there are at least two 11s that are separated by one or more 00s).