You can post such questions in Discrete Math or Math Topics forums.

Each row is an arithmetic progression with the initial term a₁ = 2, common difference d = 1 and the number of terms n = y. The sum of the first n terms of arithmetic progression is (n/2)(2a₁ + (n-1)d) = (y/2)(4 + y - 1) = y(y + 3)/2. Since there are x rows, the sum of all values in the matrix is xy(y + 3)/2.

Here are several remarks.

It is not clear whether "value" means sum, product or something else. You seem to need the sum of all numbers in the matrix.

From what you say, it is not that each column is the same (as any other column), but in each column all numbers are the same.

In mathematics, usually x refers to horizontal dimension and y refers to vertical dimension.

I though you said +1 for eachcolumnthereafter.