Symmetric squares wrt centre of 4x4 square add to 17
Source:
December 6, 2010
linear algebramatrixnumber theory unsolvednumber theory
Problem Statement
Numbers are written in a square matrix so that the sum of the numbers in every row, every column, and every diagonal is the same and furthermore that the numbers and lie in opposite corners. Prove that the sum of any two numbers symmetric with respect to the center of the square equals .