<t> if n is even n/2 eigenvalues are 0 and eigenvectors are [1, 0 , 0,..,0, 0, -1], [0, 1, 0,.., 0, -1, 0], [0, 0, 1,.., -1, 0, 0], ...n/2 eigenvalues are 2 and eigenvectors are [1, 0 , 0,..,0, 0, 1], [0, 1, 0,.., 0, 1, 0], [0, 0, 1,.., 1, 0, 0], ... if n is odd then (n-1)/2 eigenvalues are 0, (n-1)...