You could loop through the points and obtain a distance matrix dist
thr=1e-5; % example
% thresholding distances which are nearly exactly one, and finding the number of points that obey it for each point. The threshold of 1e-5 is so that points which are not exactly one unit away, but are 0.99999 units away will be included.
neighbour_pts=A(dist_th==3,:) % finds points that have 3 such neighbours
Hope this helps.