What is the wavelength of the photons emitted by hydrogen atoms when they undergo n=5 to n=4 transitions

I thought I was doing this problem correctly, but I am still getting the answer wrong, could anyone help me out?

w = wavelength in nm

w = 10^9 / [ R * (1/n1^2 - 1/n2^2) ]
w = 10^9 / [ 10 973 732 * (1/4^2 - 1/5^2) ]
w = 4050 nm

use the formula

E= Rh(1/nf - 1/ni) bohrs equation Rh is a constant

E=hv
once u find the energy use Labda=c/v h is planks constant or

u can use this with any element that has one election configuration. He +, Li +2