What would be maximum wavelength for Brackett series of hydrogen-spectrum?

$\begin{array}{l}\frac{1}{\mathrm{\lambda }}={\mathrm{Rz}}^2\left[\frac{1}{{\mathrm{n}}_1^2}-\frac{1}{{\mathrm{n}}_2^2}\right];\frac{1}{\mathrm{\lambda }}=1.097\times {10}^7\left[\frac{1}{4^2}-\frac{1}{5^2}\right]\\ \frac{1}{\mathrm{\lambda }}=1.097\times {10}^7\frac{9}{16\times 25};\mathrm{\lambda }=\frac{16\times 25}{9\times 1.097\times {10}^7}\\ =40.519\times {10}^{-7}=40519\times {10}^{-10}=40519{\mathrm{A}}^0\end{array}$