Hi,

I am intereste in calculating how many "magic sudokus" it's possible to create. A "magic sudoku" is a normal sudoku with an extra constraint:

in each of the 9 3x3 squares the sum of each row and col must be the same (15).

I have read about the difficulty in calculating the number of regular sudokus but I reckon it's possible to calculate the numbers when it's a magic sudoku. The number of possible 3x3 squares where the sum of each row and col is 15 should be each to calculate.

I have written a simple program i c to generate random "magic sudokus" but I am interested in knowing how many it's possible to make. I have a hunch that it's not that many.

Here's some output examples from my program:

1 9 5 | 6 7 2 | 3 4 8

8 4 3 | 1 5 9 | 7 2 6

6 2 7 | 8 3 4 | 5 9 1

---------------------

2 7 6 | 9 1 5 | 8 3 4

4 3 8 | 2 6 7 | 1 5 9

9 5 1 | 4 8 3 | 6 7 2

---------------------

7 6 2 | 3 4 8 | 9 1 5

5 1 9 | 7 2 6 | 4 8 3

3 8 4 | 5 9 1 | 2 6 7

1 9 5 | 7 2 6 | 3 8 4

8 4 3 | 5 9 1 | 7 6 2

6 2 7 | 3 4 8 | 5 1 9

---------------------

5 1 9 | 8 3 4 | 2 7 6

7 6 2 | 1 5 9 | 4 3 8

3 8 4 | 6 7 2 | 9 5 1

---------------------

2 7 6 | 4 8 3 | 1 9 5

9 5 1 | 2 6 7 | 8 4 3

4 3 8 | 9 1 5 | 6 2 7

8 6 1 | 2 9 4 | 3 5 7

3 7 5 | 6 1 8 | 4 9 2

4 2 9 | 7 5 3 | 8 1 6

---------------------

5 3 7 | 8 6 1 | 2 4 9

9 4 2 | 3 7 5 | 6 8 1

1 8 6 | 4 2 9 | 7 3 5

---------------------

7 5 3 | 1 8 6 | 9 2 4

2 9 4 | 5 3 7 | 1 6 8

6 1 8 | 9 4 2 | 5 7 3