5

Part of 1997 India National Olympiad

Problems(1)

Yet another array!

Source: INMO 1997 Problem 5

Find the number of

4 \times 4

array whose entries are from the set

\{ 0 , 1, 2, 3 \}

and which are such that the sum of the numbers in each of the four rows and in each of the four columns is divisible by

4

combinatorics unsolvedcombinatorics