Magic squares: would you believe…?
David L. Pagni · The Arithmetic Teacher · 1974
A magic square of nth order is a square array of n rows and n columns whose components are n^2 distinct integers. Furthermore, the sum of the numbers in any row, column, or main diagonal must always equal a constant—the “magic constant.– The array in figure I, then, is a magic square of 3rd order whose magic constant is the number 15.