Criss Cross (noch nicht übersetzt)
Problem 166
A 4x4 grid is filled with digits d, 0 ≤ d ≤ 9.
It can be seen that in the grid
6 3 3 0
5 0 4 3
0 7 1 4
1 2 4 5
the sum of each row and each column has the value 12. Moreover the sum of each diagonal is also 12.
In how many ways can you fill a 4x4 grid with the digits d, 0 ≤ d ≤ 9 so that each row, each column, and both diagonals have the same sum?