Let’s play with Magic Squares. The rules are simple.
For a given number, output a magic square where numbers in all rows, columns and both diagonals sum to the same constant. For example, solving the problem for the number 3 would generate a square where the sum calculated in any direction would equal 15.
2 7 6
9 5 1
4 3 8
Solving for 5 might render the following where all combinations add up to 65:
23 12 01 20 09
04 18 07 21 15
10 24 13 02 16
11 05 19 08 22
17 06 25 14 03
What I like about the problem is there’s some math, it’s solvable and it should act as a stepping stone to solving harder problems like Sudoku.
And, believe it or not, you can find information about magic square at Wikipedia -- http://en.wikipedia.org/wiki/Magic_square.
The idea comes from Anarchy Golf: http://golf.shinh.org/p.rb?Magic+square