The electron in a hydrogen atom makes a transition $n_1\to n_2$, where $n_1$ and $n_2$ are the principal quantum numbers of the two states. Assume the Bohr model as valid in this ease. The frequency of the orbital motion of the electron in the initial state is $\frac{1}{27}$ of that in the final state. The possible values of $n_1$ and $n_2$ are