Permutations of NxN matrix with equal summation of any row elements or column elements (N being odd number)





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The matrix NxN has N rows and columns. It has all unique elements starting from 1 to (N^2). The condition is the summation of any row elements should be equal to summation of any other row or column elements.



Example: For 3x3 matrix, one of the possible combination looks like following.



4 8 3

2 6 7

9 1 5



Now the question is how many possible combinations can occur to satisfy the given condition of given NxN matrix where N is any odd number?



Thanks for the help in advance.



Patrick










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    1















    The matrix NxN has N rows and columns. It has all unique elements starting from 1 to (N^2). The condition is the summation of any row elements should be equal to summation of any other row or column elements.



    Example: For 3x3 matrix, one of the possible combination looks like following.



    4 8 3

    2 6 7

    9 1 5



    Now the question is how many possible combinations can occur to satisfy the given condition of given NxN matrix where N is any odd number?



    Thanks for the help in advance.



    Patrick










    share|improve this question

























      1












      1








      1








      The matrix NxN has N rows and columns. It has all unique elements starting from 1 to (N^2). The condition is the summation of any row elements should be equal to summation of any other row or column elements.



      Example: For 3x3 matrix, one of the possible combination looks like following.



      4 8 3

      2 6 7

      9 1 5



      Now the question is how many possible combinations can occur to satisfy the given condition of given NxN matrix where N is any odd number?



      Thanks for the help in advance.



      Patrick










      share|improve this question














      The matrix NxN has N rows and columns. It has all unique elements starting from 1 to (N^2). The condition is the summation of any row elements should be equal to summation of any other row or column elements.



      Example: For 3x3 matrix, one of the possible combination looks like following.



      4 8 3

      2 6 7

      9 1 5



      Now the question is how many possible combinations can occur to satisfy the given condition of given NxN matrix where N is any odd number?



      Thanks for the help in advance.



      Patrick







      combinations permutation probability






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      asked Nov 23 '18 at 23:35









      PatrickPatrick

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          The best available answer is, "A heck of a lot."



          If you add the condition "same sum down the diagonal", these are magic squares. As http://oeis.org/A006052 notes, the count of magic squares is known for n = 1, 2, 3, 4, and 5. The exact answer for 6 is not known, but it is in the order of 10**20.



          Your counts will be higher still because you lack the diagonal condition. But the computational complexities are the same. Brute force will give you answers for n = 1, 2, 3, and 4 fairly easily. 5 will be doable. 6 will be intractable. 7 will be "no hope".






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            1 Answer
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            The best available answer is, "A heck of a lot."



            If you add the condition "same sum down the diagonal", these are magic squares. As http://oeis.org/A006052 notes, the count of magic squares is known for n = 1, 2, 3, 4, and 5. The exact answer for 6 is not known, but it is in the order of 10**20.



            Your counts will be higher still because you lack the diagonal condition. But the computational complexities are the same. Brute force will give you answers for n = 1, 2, 3, and 4 fairly easily. 5 will be doable. 6 will be intractable. 7 will be "no hope".






            share|improve this answer




























              0














              The best available answer is, "A heck of a lot."



              If you add the condition "same sum down the diagonal", these are magic squares. As http://oeis.org/A006052 notes, the count of magic squares is known for n = 1, 2, 3, 4, and 5. The exact answer for 6 is not known, but it is in the order of 10**20.



              Your counts will be higher still because you lack the diagonal condition. But the computational complexities are the same. Brute force will give you answers for n = 1, 2, 3, and 4 fairly easily. 5 will be doable. 6 will be intractable. 7 will be "no hope".






              share|improve this answer


























                0












                0








                0







                The best available answer is, "A heck of a lot."



                If you add the condition "same sum down the diagonal", these are magic squares. As http://oeis.org/A006052 notes, the count of magic squares is known for n = 1, 2, 3, 4, and 5. The exact answer for 6 is not known, but it is in the order of 10**20.



                Your counts will be higher still because you lack the diagonal condition. But the computational complexities are the same. Brute force will give you answers for n = 1, 2, 3, and 4 fairly easily. 5 will be doable. 6 will be intractable. 7 will be "no hope".






                share|improve this answer













                The best available answer is, "A heck of a lot."



                If you add the condition "same sum down the diagonal", these are magic squares. As http://oeis.org/A006052 notes, the count of magic squares is known for n = 1, 2, 3, 4, and 5. The exact answer for 6 is not known, but it is in the order of 10**20.



                Your counts will be higher still because you lack the diagonal condition. But the computational complexities are the same. Brute force will give you answers for n = 1, 2, 3, and 4 fairly easily. 5 will be doable. 6 will be intractable. 7 will be "no hope".







                share|improve this answer












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                answered Nov 27 '18 at 19:01









                btillybtilly

                27.1k24053




                27.1k24053
































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