In the framework of seesaw mechanism with three neutrino flavors, we propose tentatively an efficient parametrization for the spectra of Dirac and righthanded Majorana neutrino mass matrices in terms of three free parameters. Two of them are related to (and determined by) the corresponding parameters introduced previously for the mass spectra of charged leptons and up and down quarks. The third is determined from the experimental estimate of solar \Delta m²₂₁. Then, the atmospheric \Delta m²₃₂ is  predicted close to its experimental estimation. With the use of these three parameters all light active-neutrino masses m₁ < m₂ < m₃ and heavy sterile-neutrino masses M₁ < M₂ < M₃ are readily evaluated. The latter turn out much more  hierarchical than the former. The lightest heavy mass M₁ comes out to be of the order O(10⁶GeV) so, it is too light to imply that the mechanism of baryogenesis through thermal leptogenesis might work.

PACS numbers: 12.15.Ff, 12.15.Hh, 14.60.Pq