Function name: triangular Parameters: integer Returns: a list Description: Write a function called triangular that accepts one integer parameter that returns a list with the same number of terms as the value of the parameter. If the parameter is zero or a negative number, you should return an empty list A triangular number is the sum of a positive integer and all the integers before it. The series is as follows: 1, 3, 6, 10, 15, 21