Answer:
1, 2, 6 , 24 , 120
Explanation:
d(n) = n d(n - 1) is a recursive formula
with n the term number and d(n - 1) the preceding term
this allows any term in the sequence to be found from the preceding term
given the first term d(1) = 1, then
d(2) = 2d(2 - 1) = 2d(1) = 2 × 1 = 2
d(3) = 3d(3 - 1) = 3d(2) = 3 × 2 = 6
d(4) = 4d(4 - 1) = 4d(3) = 4 × 6 = 24
d(5) = 5d(5 - 1) = 5d(4) = 5 × 24 = 120
the first 5 terms in the sequence are 1 , 2 , 6 , 24 , 120