Returns the magic matrix
A = makematrix_magic ( n )
a 1-by-1 matrix of doubles, integer value, the size of the matrix to return
a n-by-n matrix of doubles, integer values
Returns the magic matrix of size n. The sum over the rows or the sum over the columns is always the same. This is a port of Scilab's magic.f
The algorithm is different if n is a multiple of 4, an even or odd number.
"Mathematical recreations and essays", 12th ed., by w. w. Rouse Ball and h. s. m. Coxeter