The coefficient of $x^2$ in expansion of the product
(2-$x^2$).($(1 + 2x + 3x^2)^6$ + $(1-1 4x^2)^6$) is :

$g(x)=4 x, P(y)=\frac{(1+y)^{n}}{1-y}$

Coefficient of $x^ {15}$ in $(1+x+x^ {3}+x^ {4})$^ {n} is

The cofficient of $x^{32}$in the expansion of $( x^4 - \frac {1}{x^3})^{15}$is