MATLAB: How to modify for loop of i and j to get value odd number

Question

I2 = imread('......');
I2 = rgb2gray (I2);
N=8; %N= window size (8x8)
[L,L]=size(I2);
L2=L/N;
S=zeros(L,L);
for i=1:L2
for j=1:L2
S=I2((i-1)*N+1:i*N,(j-1)*N+1:j*N);
theSum(i, j) = sum(S(:));
end;
end;

Answer 1

Do you mean, for example,

i=1:2:L2

?

This would loop over i = 1,3,5, ..., L2