Value of n for the energy level transition that produce lamb

[mss90]

Homework Statement

A wavelength of 410.2*10^-9m is emitted by the hydrogen atom in a high voltage discharge tube. what are the initial and final values of the quantum number n for the energy lvl transition that produces this wavelength?

Homework Equations

1/(lambda) = R * (1/2^2 - 1/n^2): Lyman series?

The Attempt at a Solution

I have used this equation to figure out (lambda) but never the other way around.
I tried to solve for n but it doesn't make sense. How can I know which series to solve n for?
At first I thought that it had to be Lyman as Z=1 for hydrogen and subsequently n=1 but no.
The answer is ni = 6 and nf = 2.

 

[Thyphon]

use Rydberg eq.

RH=10973732 m^(-1)