hi, try using the little x2 button in the post response
basically, an electron can go between any two orbital values
it can go from n1 to n2; n1 to n3, etc.
but of course, the energy that is required to go from, say, n3 to n4 is the same as the energy required to go from n4 to n3
Also, photons are only emitted when an electron goes from a higher energy orbital to a lower energy orbital. In other words, only worry about going from some nx to ny where y < x
you should have a formula for determining the energy of an electron at some orbital, and an equation for the energy of some photon with a given wavelength. If you take the difference between two orbitals, then that will tell you how much energy was released/absorbed when the electron went between them.
Going from n3 to n2 will have some energy difference, use that energy difference to find the wavelength