On Pillai's Problem involving Lucas sequences of the second kind

In this paper we consider the Diophantine equation $V_n - b^m = c$ for given integers $b,c$ with $b \geq 2$, whereas $V_n$ varies among Lucas-Lehmer sequences of the second kind. We prove under some technical conditions that if the considered equation has at least three solutions $(n,m)$, then there is an upper bound on the size of the solutions as well as on the size of the coefficients in the characteristic polynomial of $V_n$.