2¹⁰ = 1024
2²⁰ = 1048576
Note that raising 2 to each of the first two multiples of 10 results in a number whose first digit is 1.

Find the smallest multiple of 10 where 2 raising to that power results in a number that does not begin with 1.

(In reply to re(2): worked out by Charlie)

That was my main point, - there are numerous samples before 300.

Posted by Ady TZIDON on 2015-04-17 01:48:20