QuasiNormalModesGet the code!
A Mathematica package for computing quasinormal modes (QNMs) in Schwarzschild and Kerr spacetime. The package introduces a new function
QuasiNormalMode[s, l, m, n, a]
$s$ - is the spin-weight of the perturbing field
$l$ - is the multipolar index
$m$ - is the azimuthal index
$n$ - is the overtone number
$a$ - is the black hole spin parameter
Currently the Schwarzschild ($a=0$) case works well. For QNMs in Kerr you are not guaranteed that the mode returned corresponds to the specified overtone number (though often it will).
Additional documentation can be found in the Mathematica Documentation included with the package.