# Inverting a series

How do I invert the following,

 \[Rho]=r + b0 Sum[Pochhammer[1/2, k]/(k! ((1 - q) k - 1)), {k, 0, \[Infinity]}] + b0^(1 - q)/(2 q) r^q + O[r^(2 q - 1)]


to get $$r(\rho)$$? To note, $$q<0$$ and $$b_{0}$$ is some positive constant.

• Have you tried InverseSeries? – Henrik Schumacher Jan 27 at 9:20
• Yes, but it does not give any output. – user583893 Jan 27 at 13:23