Matrix element of Position Operator For Hydrogen Atom

[physics2004]

Find <nlm|(1/R)|nlm> for the hydrogen atom (nlm = 211), R is just the radial position Operator (X2 + Y2 + Z2)½.

[physics2004]

I got (1/2)*((z/ao)**9))

ao = bohr radius

Z= Atomic #


would help if someone could double check for me kind of messy math