Which formula can be used to describe the sequence?

-2 2/3, -5 1/3, -10 2/3, -21 1/3, -42 2/3.

A: f(x + 1) = –2f(x)

B: f(x + 1) = -1/2 f(x)

C: f(x + 1) = 1/2 f(x)

D: f(x + 1) = 2f(x)