Taking G.P to a new level

Calculus Level pending

How many increasing 3 -term geometric progessions can be obtained from the sequence $$1, 2 , 2^{2} , 2^{3} , .................... , 2^{n}$$

DETAILS - $$\{2^{2} , 2^{5} , 2^{8}\}$$ is a 3-term G.P for $$n \geq 8$$

×