Which transition in ${\mathrm{Li}}^{2+}$ would have the same wavelength as the $2 \to 4$ transition in He+ ion?

The transition in given ion which would have the same wavelength as the 2-> transition in ${\mathrm{He}}^{+}$ ion:

$2^2\left[\frac{1}{2^2}-\frac{1}{4^2}\right]=3^2\left[\frac{1}{n_1^2}-\frac{1}{n_2^2}\right]$

$\Rightarrow \frac{n_1}{3}=1$ and $\frac{n_2}{3}=2$