#### Answer

$1, 2, 6, 24, 120$

#### Work Step by Step

For the first five terms, we need to find: $a_1, a_2, a_3, a_4$, and $a_5$
$a_1 = 1 $ by definition
$a_{n+1} = na_n$
$a_1 = 1$
$a_2 = 2(1) = 2$
$a_3 = 3(2) = 6$
$a_4 = 4(6) = 24$
$a_5 = 5(24) = 120$