Given a geometric sequence in the table below, create the explicit formula and list any restrictions to the domain.
n an
1 -4
2 20
3 -100
An=-5(-4)^n-1 where n is greater or equal to 1
An=-4(5)^n-1 where n is greater or equal to 1
An=-4(5)^n-1 where n is greater than or equal to -4
An=5(-4)^n-1 where n is greater then or equal to -4