25 Jun 2011 by Espen Harlinn
A square is magic if each of the rows, columns, and diagonals add up to the same total. So, for example, the square 25 4 19 10 16 22 13 28 7is magic, since every row, column, and diagonal adds up to 48. Of the nine entries, three (4, 16 and 25) are perfect squares.The problem...