powers-of-2

Powers of 2

Complete the function that takes a non-negative integer n as input, and returns a list of all the powers of 2 with the exponent ranging from 0 to n (inclusive).

Examples

n = 0  ==> {1}        // {2^0}
n = 1  ==> {1, 2}     // {2^0, 2^1}
n = 2  ==> {1, 2, 4}  // {2^0, 2^1, 2^2}