input: Write a python function to generate a list of powers from 0 to 15 for a given number.
  assert power_list(2) == [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768]
  assert power_list(3) == [1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 59049, 177147, 531441, 1594323, 4782969, 14348907]
  assert power_list(1) == [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
output: def power_list(n):
      return [n ** i for i in range(16)]