If \([t]\) denotes the greatest integer \(\le t\), then the value of \(\dfrac{3(e-1)}{e}\displaystyle \int_{1}^{2} x^{2} e^{[x]+[x^{3}]} dx\) is:
\(e^{8} - e\)
\(e^{7} - 1\)
\(e^{9} - e\)
\(e^{8} - 1\)