MathDB
A=a_ij=i^j+j^i mod 3, det A≠0

Source: SEEMOUS 2012 P1

June 9, 2021
matrixlinear algebranumber theory

Problem Statement

Let A=(aij)A=(a_{ij}) be the n×nn\times n matrix, where aija_{ij} is the remainder of the division of ij+jii^j+j^i by 33 for i,j=1,2,,ni,j=1,2,\ldots,n. Find the greatest nn for which detA0\det A\ne0.