How to only fill one line of a matrix with a given formula

I am trying to fill a 3*n matrix, with the first row being ones, the second row being 20 0 repeating. and the third row being 30 0 0 repeating.

Example:

For matrix n = 10, it should look like this

1 1 1 1 1 1 1 1 1 1

20 0 20 0 20 0 20 0 20 0

30 0 0 30 0 0 30 0 0 30

function A = specialMatrix(n)

A = zeros(3,n);

A(1,:) = 1

A(11:2:end) = 20

A(21:3:end) = 30

end

However, this does not fill up the matrix in the desired way.

How can I format my coding to fill up the matrix correctly?

Answer 1

[Voss]

function A = specialMatrix(n)
    A = zeros(3,n);
    A(1,:) = 1;
    A(2,1:2:end) = 20;
    A(3,1:3:end) = 30;
end