Concentric (3x3 in 5x5 in) 7x7 magic square

 

Start with a 3x3 magic square and put a border around the square again and again to get a 3x3 in 5x5 in 7x7 in 9x9 in ... magic square.

 

 

Number + 8          Number + 12                          Concentric 7x7 magic square

                    6 1 3 43 41 39 42
        22 18 3 2 20   48 34 30 15 14 32 2
2 9 4   7 10 17 12 19   46 19 22 29 24 31 4
7 5 3   5 15 13 11 21   45 17 27 25 23 33 5
6 1 8   25 14 9 16 1   10 37 26 21 28 13 40
        6 8 23 24 4   12 18 20 35 36 16 38
                    8 49 47 7 9 11 44

                 

Download
7x7, concentric.xls
Microsoft Excel werkblad 39.5 KB