How to write a sequential algorithm

Example:

I have this algorithm A:

i=1 Columns=[1:36];

A=[(Columns(i)-1)*3+1:Columns(i)*3];

%Vector

When i=1 A=[1, 2, 3]

When i=2 A=[4, 5, 6]

When i=3 A=[7, 8, 9]

How to do another Algorithm A=?

When i=1 A=[1, 4, 7]

When i=2 A=[3, 5, 8]

and so on...

Answer 1

[Voss]

I think the first element of A when i = 2 should be 2 instead of 3. If so, then:

Columns=[1:36];
for i = 1:numel(Columns) 
    A = i+[0 3 6];
end