Let us say that a magic square is a 4x4-square grid of numbers 1,...,16 in some order such that the sum of numbers of every horizontal row or vertical column is constant. How can I make the program to find nth magic square for given n? Here, the nth means that if we replace 1 by A, 2 by B and so on and we read the square from left to right, up to bottom, we order the word by alphabetical order. Example
1 2 15 16
6 11 7 10
13 12 4 5
14 9 8 3
corresponds ABOPFKGJMLDENIHC
and
1 2 15 16
6 11 7 10
14 9 8 3
13 12 4 5
corresponds ABOPFKGJNIHCMLDE so ABOPFKGJMLDENIHC comes before ABOPFKGJNIHCMLDE.