The recurrence $a_n = 10a_{n-1} - 25a_{n-2}$ has characteristic equation $r^2 - 10r + 25 = (r-5)^2 = 0$, giving a double root at $r = 5$. The general solution is $a_n = (c_1 + c_2 n) \cdot 5^n$.

Given $a_0 = 2$ and $a_1 = 15$, find $c_2$.