  Let $S := \{p_1,\ldots ,p_{\ell}\}$ be a finite set of primes and denote by
$\mathcal{U}_S$ the set of all rational integers whose prime factors are all in
$S$. Let $(U_n)_{n\geq 0}$ be a non-degenerate linear recurrence sequence with
order at least two. In this paper, we study the finiteness result for the
solutions of the Diophantine equation $U_n + U_m = z_1 +\cdots +z_r,$ where
$n\geq m$ and $z_1, \ldots, z_r\in \mathcal{U}_S$. We also study the
Diophantine equation $U_n + U_m =wy^q$ with $w$ is a non-zero integer. In this
case, we show that sum of two terms of recurrence sequence $(U_n)_{n\geq 0}$
does not contain any $q$-th power if $q$ is large enough.
