# 1248136

**Number Theory**Level 5

Andy's little brother is playing a game with the list of powers of \(2:\) \[1,2,4,8,16,32, \ldots \] He chooses randomly one of the powers and then writes down a three-digit number made out of its first digit, then the first digit of the next number, then the first digit of the next number. How many possible different three-digit numbers can he write down?

**Details and assumptions**

As an explicit example, if Andy's brother chooses number \(8\), then he writes down the first digits of 8, 16 and 32, which gives \(813.\)