Описание тега magic-square
In recreational mathematics, a magic square is an arrangement of numbers (usually integers) in the form of a square grid, where the numbers in each row, and in each column, and the numbers in the forward and backward main diagonals, all add up to the same number.
A magic square has the same number of rows as it has columns, and in conventional math notation, "n" stands for the number of rows (and columns) it has.
Thus, a magic square always contains n2 numbers, and its size (the number of rows [and columns] it has) is described as being "of order n". A magic square that contains the integers from 1 to n2 is called a normal magic square. (The term "magic square" is also sometimes used to refer to any of various types of word squares.)
Wikipedia:
http://en.wikipedia.org/wiki/Magic_square