  For a singular oscillator, the Schrodinger equation is obtained an equation
of eigenvalues, and the dependence of energy on the self-adjoint extension
parameter is established. It is shown that the self-adjoint extension violates
the well-known property of equidistance of energy levels for the oscillatory
potential, well-known in quantum mechanics. The concept of quantum defect is
generally introduced, and the wave function of the problem is written as a
single function.
