A sequence can be generated using an-3a(n-1) where a1-6 and n is a whole number greater than 1. What are the first four terms of this sequence?

The correct sequence is 6, 18, 54, 162. Let's test it with the formula:

a(n) = an-3a(n-1)
a(2) = 2-3a(1) = 2 - 3*6 = -16
a(3) = 3-3a(2) = 3 - 3*18 = -51
a(4) = 4-3a(3) = 4 - 3*54 = -156

Therefore, the first four terms of this sequence are 6, 18, 54, 162.