Magic squares of single-even order (n=6, 10, 14, …) are known to be difficult to construct. One reason e.g. can be recognized, if you divide the square in its four quadrants. This time, these quadrants are of odd order, so that it is impossible to fill them in a symmetrical order. You always have to balance the elements to get equal sums.
|al-Haytham (n ⩾ 10)|
|Bachet – Labosne|
|Wang Fat – Zhou Ming|
|Unknown author (Method 1)|
All algorithms are described in detail in chapter Single-even Magic Squares (german: Einfach-gerade Ordnungen) together with some other PDF documents.