input: Write a python function to determine the count of subsequences with a product less than a given value k for a given array of non-negative integers.
  assert no_of_subsequences([1, 2, 3, 4], 10) == 11
  assert no_of_subsequences([4, 8, 7, 2], 50) == 9
  assert no_of_subsequences([5, 6, 7, 8], 15) == 4
output: def no_of_subsequences(arr, k):
      def count_subsequences(index, prod):
          if prod >= k:
              return 0
          if index == len(arr):
              return 1 if prod < k else 0
          including = count_subsequences(index + 1, prod * arr[index])
          excluding = count_subsequences(index + 1, prod)
          return including + excluding
      
      return count_subsequences(0, 1) - 1