The highest frequency of the emitted photon in the Paschen series of spectral line of the hydrogen atom is 

frequency of the emitted photon in Paschen series is given by $\nu =Rc\left(\frac{1}{3^2}-\frac{1}{n^2}\right) for highest frequency n=\infty$

${\nu }_{highest }=\frac{Rc}{9}=\frac{1.097\times {10}^7\times 3\times {10}^8}{9}=3.7\times {10}^{14}$