Answer
$$\prod_{k=2}^{4} (k^2-1)$$
Work Step by Step
The sequence involves a product so product notation will be used.
The factors are of the form $(k^2-1)$ where $k$ is counting number.
$k$ varies from 2 to 4.
Thus, the product notation whose expanded form is given is:
$$\prod_{k=2}^{4} (k^2-1)$$
