Question

(1,12) (2,76) (3,108) (4,124) (5,132) (6,136) (7,138) (8,139) (9,139.5)

What is the rule or equation?

Answer 1

76-12 = 64 for n = 2

108-76 = 32 for n = 3
124 -108 = 16
132 - 124 = 8
136 - 132 = 4
138 - 136 = 2
139 -138 = 1
139.5- 139 = .5

Yn+1 - Yn = 64/2^(n-1)
or
Y1 = 12
Yn+1 = Yn + 64/2^(n+1)