input: Write a function to calculate an exponential series given a base value `x` and a limit value `n`. The function should return the sum of the series where each term is `x` raised to the power of `i` (i ranges from 0 to `n` inclusive).
  
  def exponential_series(x, n):
      sum = 0
      for i in range(n+1):
          sum += x ** i
      return sum
  
  assert exponential_series(2, 3) == 15
  assert exponential_series(3, 2) == 13
  assert exponential_series(1, 5) == 6
  assert exponential_series(0, 4) == 1
  assert exponential_series(5, 0) == 1
output: def exponential_series(x, n):
      sum = 0
      for i in range(n+1):
          sum += x ** i
      return sum