Write the Maclaurin series for $f(x) = 3x^{2}\sin\!\left(7x\right)$ as $\displaystyle \sum_{n=0}^\infty c_n x^n.$
Find the following coefficients.

$c_3$	=
$c_4$	=
$c_5$	=
$c_6$	=
$c_7$	=