Classical mechanics and 1/n expansion

Classical approximation (n,l → ∞) and 1/n expansion for quantum mechanics problems are considered. The recurrent method of calculation of members of a sequence of 1/n expansion for energy and wave functions (both for real and quasistationary states) is described. These results are considered by an example of the Yukawa, Hulthen, cone, etc. potentials. For potentials considred already two-three memebers of 1/n expansion determine the energy levels with 0.1% accuracy (even for small quantum numbers)