Let the sum of the coefficients of the first three terms in the expansion of (x-3/x^2)^n, x ≠ 0. n ∈ N, be 376. Then the coefficient of x^4 is ____.

Let the sum of the coefficients of the first three terms in the expansion of $\displaystyle \left(x-\frac{3}{x^2}\right)^n, x \neq 0 . n \in \mathbb{N}$, be 376. Then the coefficient of $\displaystyle x^4$ is $\displaystyle \_\_\_\_$.