How can I insert a sequental columns in a matrix with a lag of three columns?

Dear all,

I have a two-dimensional matrix A, which contains 914 columns. I would like to create a matrix B and insert every columns from A, so that

Column 1 from A goes to column 1 in B

column 2 from A goes to column 4 in B

column 3 from A goes to column 7 in B...and so on

I tried that code, but it gives me an error:

B=nan(size(A,1),size(A,2)*3);
for i=4:3:size(B,2);
    for ii=1:size(A,2);
    data(:,i)=A(:,i-2*ii);
    end
end

Answer 1

[Azzi Abdelmalek]

 A=randi(9,4,3) 
n=size(A,2)
B=nan(size(A,1),n*3)
idx=1:3:size(B,2) 
B(:,idx)=A

[Ekaterina Serikova]

Thanks a lot!