1, 2, 4, 8, 16, what is the number of 2013? What if it's the nth number? Is it the N-1 power of 2?

1, 2, 4, 8, 16, what is the number of 2013? What if it's the nth number? Is it the N-1 power of 2?

1,2,4,8,16, the number 2013 is the power of 2
It's easy to see from the numbers 1, 2, 4, 8 and 16
If it is the nth number, the result is n-1 power of 2