Multiply and shift ?

I would like to have a code that can generate the maltiplication for x after shifting them many time

x=[1 2 4 1 3 4 5 1 3]

I would like to have a loop that can generate the autocorrlation for x with itself.

to illustrate;

x*x

R(1)=sum([1 2 4 1 3 4 5 1 3]*[1 2 4 1 3 4 5 1 3])/Length(x)

R(2)=sum([ 2 4 1 3 4 5 1 3]*[1 2 4 1 3 4 5 1 ])/Length(x-1)

and so forth until the R(N) computed

Answer 1

[Catalytic]

R = ifftshift(xcorr(x,'unbiased'))

[Matt J]

Or, if you don't have the Signal Processing ToolBox,

e=ones(size(x));  
R=ifftshift( conv(x,flip(x))./conv(e,e) );

[Willim]

The results for the both codes you provide are not same

[Catalytic]

The differences I see are super-small.

x=[1 2 4 1 3 4 5 1 3];
e=ones(size(x));  


R1 = ifftshift(xcorr(x,'unbiased'));
R2=ifftshift( conv(x,flip(x))./conv(e,e) );

>> difference=max(abs((R1-R2)))

difference =

   3.5527e-15