Question : Formula to calculate all position for given matrix

Hi, I need to calculate how many combination are possible for a matrix.
Following an example: we consider a data set composed by 4 rows and 5 columns.
1 – 2 – 3 – 4 – 5
6 – 7 – 8 – 9 – 10
11 – 12 – 13 -14 -15
16 – 17 – 18 – 19 - 20
How many rows can be generated combining all the elements without changing their position horizontally (2 elements per column are not allowed) ?
What I need is a simple formula expressed in terms of numbers of cols and number of rows
Thanks in advance

Answer : Formula to calculate all position for given matrix

>> without changing their position horizontally
I infer that you can change their position vertically. If this is the case, then each column has 4! permutations, and their are 5 columns. So you have 4! x 4! x 4! x 4! x 4! =  (4!)^5 = 24^5 = 7962624 possible matrices.