Represent the function $\displaystyle \frac{3}{(1 - 7 x)^2}$ as a power series $\displaystyle f(x) = \sum_{n=0}^\infty c_n x^n$
$c_0 =$
$c_1 =$
$c_2 =$
$c_3 =$
$c_4 =$
Find the radius of convergence $R =$ .