  An analytical approximation for the eigenvalues of $\mathcal{PT}$ symmetric
Hamiltonian $\mathsf{H} = -d^{2}/dx^{2} - (\mathrm{i}x)^{\epsilon+2}$,
$\epsilon > -1$ is developed via simple basis sets of harmonic-oscillator wave
functions with variable frequencies and equilibrium positions. We demonstrate
that our approximation provides high accuracy for any given energy level for
all values of $\epsilon > -1$.
