Let \([x]\) denote greatest integer less than or equal to \(x\). If for \(n \in N ,\left(1-x+x^3\right)^n=\sum_{j=0}^{3 …

Let \([x]\) denote greatest integer less than or equal to \(x\). If for \(n \in N ,\left(1-x+x^3\right)^n=\sum_{j=0}^{3 n} a_j x^j\), then \(\sum_{j=0}^{\left[\frac{3 n}{2}\right]} a_{2 j}+4 \sum_{j=0}^{\left[\frac{3 n-1}{2}\right]} a_{2 j+1}\) is equal to:

[JEE Main 2021, 16 Mar (Shift 1)]