What would be maximum wavelength for Brackett series of...

For Brackett series, $n_1=4, n_2=5,6,7 \ldots \ldots \ldots\frac{1}{\lambda}=R$\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$where$R=1.09678 \times10^7 \mathrm{ m}^{-1}, called Rydberg's constant. \frac{1}{\lambda}=$R\left(\frac{1}{4^2}-\frac{1}{n_2^2}\right)$ For maximum wavelength, $n_2=5$$\begin{aligned}& \frac{1}{\lambda_{\max }}=1.09687 \times10^7 \left(\frac{1}{4^2}-\frac{1}{5^2}\right)\\ & \lambda_{\max }=40519 Å \end{aligned}$