I need to comput and display the sum and average of the cubes of the even natural numbers between 2 and n. Where n is entered by the user. Im stuck on how to average the sum of the cubes. Help Please. This is what I have so far.

```
def main():
print ("This calculates the sum of the cubes of the 1st natural numbers")
natn = eval(input("How many cube numbers do you want to sum? "))
add = 0
for i in range (natn):
add = add + i**3
print (add)
main()
```