[Solved] Python: Is There a builtin that works similar but opposite to .index()?

As an answer to:

Is there a builtin I could use to input the position and return the item in the list?

You just need to access the list with it’s index as:

>>> my_list = [1,2,4,8,16]
>>> my_list[4]
16  # returns element at 4th index

And, this property is independent of language. All the languages supports this.

Based on your edit in the question, you may write your function as:

def check_value(my_list):
    # if len is less than 2
    if len(my_list) < 2:
        if my_list and my_list[0] == 1:
            return True
        else:
            return False 
    base_val = my_list[1] # as per the logic, it should be original number i.e num**1 
    for p, item in enumerate(my_list):
        if item != base_val ** p: 
            return False
    else:
        return True

Sample run:

>>> check_value([1, 2, 4, 8])
True
>>> check_value([1, 2, 4, 9])
False
>>> check_value([1, 5, 25, 75])
False