  We analyze the distribution of the eigenvalues of the quantum-mechanical
rotating harmonic oscillator by means of the Frobenius method. A suitable
ansatz leads to a three-term recurrence relation for the expansion
coefficients. Truncation of the series yields some particular eigenvalues and
eigenfunctions in exact analytical form. The former can be organized in such a
way that one obtains suitable information about the whole spectrum of the
model.
