Find the Maclaurin series of the function $f(x) = (3 x^2) e^{- 7 x}$.
$$f(x) = \sum_{n=0}^\infty c_n x^n$$
Determine the following coefficients:
$c_1 =$
$c_2 =$
$c_3 =$
$c_4 =$
$c_5 =$