Hydrogen radial wavefunction in the first excited shell ($R_{20},R_{21}$)

Writing $\rho =r/a_0$, the normalized radial wavefunctions are $R_{20}=(2-\rho )e^{-\rho /2}/(2\sqrt{2}{a}_0^{3/2})$ and $R_{21}=\rho e^{-\rho /2}/(\sqrt{24}{a}_0^{3/2})$. Radial normalization uses $\int r^2|R{|}^{2}dr=1$. The first function has one positive radial node at $2a_0$; the second has none. Their behavior at the origin differs from that of the reduced radial function $rR$ and from the radial probability density $r^2|R{|}^2$.