To apply to atoms with multiple electron, the Rydberg formula is usually modified by changing Z with Z − b or n with n − b exactly where b is constant symbolizing a screening outcome due to internal-shell and other electrons (see Electron shell plus the later discussion in the https://gandula.de/2024/08/01/ein-leitfaden-fur-anfanger-zum-verstandnis-der-funktionsweise-von-bohrmaschinen/