How to find four neighbours of a pixel in an indexed image?

I have an indexed image with 7 indices. I have to find how many neighbors of each pixel with index=7 are pixels with index = 6.

I wrote the code below, however, I am not getting a correct histogram.

[A,map] = imread('FCLS_crop_20190627_1.tif');
for i=1:numel(A)
    if A(i)==7
            [ix,ixn] = ixneighbors(A,i);
            fprintf('index[%d]',ix);
            fprintf('\n');
            neigh = A(ixn);
            fprintf('%d\t',neigh); 
            numberOfNonZeros = nnz(neigh==6);
            NumofOnes(i) = numberOfNonZeros;
            
    end
end
hist(NumofOnes);
xlabel('Number of Neighbors')
ylabel('Frequency')

[KSSV]

Try knnsearch.

[Rik]

Or a loop with calls to circshift so you can test equality for the entire array at once?

[Anwesha Sharma]

Thanks.