is it possible to obtain a closed-form solution w.r.t. ${P_j:\forall j}$ (or in terms of special functions) for the following equations:

$\frac{\lambda}{\mu}P_0=P_1$

$\frac{\lambda}{\mu}P_j=P_{j+1}+P_{j+2}+\dots+P_{2j+1}$ for $j=1,2,....$