Answer:
5
Explanation:
Usually, the sequence is
where n is a postive number.
From the question,

if n = 2 ;

Thus, we got
.
if n = 3 ;


Thus, we got
.
if n = 4 ;


Thus, we got
.
***There are many ways to solve this question
example:


Substitute n with 2, 3, 4
Then, we will get 3 equations.
Sum them up;
We will get
