def discrec(self):
    """
    Returns the discriminant of the reciprocal form.

    EXAMPLES::

        sage: Q = DiagonalQuadraticForm(ZZ, [1,1,37])
        sage: Q.disc()
        148
        sage: Q.discrec()
        5476
        sage: [4 * 37, 4 * 37^2]
        [148, 5476]

    """
    return self.reciprocal().disc()