#### Answer

$a_{n}=na_{n-1}$

#### Work Step by Step

Sequence starts with 1 so
$a^{1}=1$
Then
$a_{2}=2*1$
$a_{3}=3*2=3*a_{2}$
$a_{4}=4*6=4*a_{3}$
$a_{5}=5*24=5*a_{4}$
Notice that the first factor in the factored form of the term;s value is the same as the term number, while the second factor is the same as the value of the previous term.
Thus, letting $n$ be the term number, the recursive formula for the sequence is:
$a_{n}=na_{n-1}$