Q:

How do I create a n*n matrix with a Do loop?

I'm trying to create an n*n matrix that would follow this criteria
1    2    3   ...  n
n+1  n+2  n+3 ...  2n
2n+1 2n+2 2n+3 ... 3n
 .                  .
 .                  .
 .                  .
(n-1)n+1 ........ n^2

How would I be able to create this matrix using a table or a do loop?
This is what I've created so far, but it doesn't follow the criteria unfortunately.
n = Input["What positive integer would you like to start your matrix with?"];
x = ConstantArray[0, {n, n}];
Do[x[[i, j]] = i + j, {i, 1, n}, {j, 1, n}]
x // MatrixForm

A:

Better to use Table:
n = Input["What positive integer would you like to start your matrix with?"];

Table[i + j*n, {j, 0, n - 1}, {i, n}]

A:

I suggest you define a function, m to create your matrix. Here are two possible for m
Carl Woll
m[n_] := Partition[Range[n^2], n]

m_goldberg
m[n_] := ArrayReshape[Range[n^2], {n, n}]

In either case
m[3]//MatrixForm

