Sum of n natural numbers using while loop in python

Question

The question was tp :write a program to find the sum of n natural numbers using while loop in python.

n = int(input("Enter a number: "))
i = 1
while i<n:
    print(i)
    i = i + 1

this is what I have done s far... can not understand what to do next.

Answer 1

with a while loop the sum of natural numbers up to num

num = 20
sum_of_numbers = 0
while(num > 0):
    sum_of_numbers += num
    num -= 1
print("The sum is", sum_of_numbers)

Answer 2

You can either follow Alasgar's answer, or you can define a function with the formula for this particular problem.
The code's gonna be something like this:

def natural(n):
    sumOfn = (n * (n + 1))/2

terms = int(input("Enter number of terms: "))
natural(terms)