combinatorics - Number of solutions of $x_1 + 2x_2 + 3x_3 + cdots + n x_n = p$

Given a non-negative integer $p$. What is the number of solutions of $x_1+2x_2+3x_3 + \cdots + nx_n = p$, where the $x_i$'s are non-negative integers.

Can we answer this by using number of solutions of $x_1+x_2+x_3 + \cdots + x_m = q$ for any $m,q$?