def AICc(N, rho, k, norm=True):
    """corrected Akaike information criterion

    .. math:: AICc(k) = log(\\rho_k) + 2 \\frac{k+1}{N-k-2}


    :validation: double checked versus octave.
    """
    from numpy import log, array
    p = k
    res = log(rho) + 2.0 * (p + 1) / (N - p - 2)
    return res
