Answer: If a1 = 16 and a2 = -8, then we can write a recursive formula for the nth term of the sequence as follows:
an = a(n-1)/2
This formula states that the nth term of the sequence is equal to the previous term (n-1) divided by 2. For example, if n = 3, then a3 = a(3-1)/2 = a2/-8/2 = 4.
We can also write this formula in terms of the initial values of the sequence as follows:
a(n) = (-1)^(n-1) * 8
This formula states that the nth term of the sequence is equal to (-1) raised to the power of (n-1), multiplied by 8. This formula will always give the correct value for the nth term of the sequence, regardless of the initial values of the sequence.