  We correct some tables and figures in [A.P. Bustamante and R.C. Calleja,
Physica D: Nonlinear Phenomena, 395 (2019), pp. 15-23, arXiv:1712.05476]. We
also report on the new computations that verify the accuracy of the data and
extend the results. The new computations have led us to find new patterns in
the data that were not noticed before. We formulate some more precise
conjectures.
