MathDB
largest integer N, for which there exists a 6xN table, so that ...

Source: Mediterranean 2018 P4 MMC

July 30, 2018
combinatoricsnumbers in a tablemaximumMediterranean

Problem Statement

Determine the largest integer NN, for which there exists a 6×N6\times N table TT that has the following properties: * Every column contains the numbers 1,2,,61,2,\ldots,6 in some ordering. * For any two columns iji\ne j, there exists a row rr such that T(r,i)=T(r,j)T(r,i)= T(r,j). * For any two columns iji\ne j, there exists a row ss such that T(s,i)T(s,j)T(s,i)\ne T(s,j).
(Proposed by Gerhard Woeginger, Austria)