# Python Program to Find Sum of Natural Numbers Using Recursion

Posted in

Vinay Khatri
Last updated on August 22, 2022

Here in this article, we have provided a python source code that can find the sum of the first n natural numbers using recursion technique.

## Prerequisite Python Program to Find Sum of Natural Numbers Using Recursion

• Python Input, Output
• Python User-Defined Function
• Python Recursion
• Python if…else statements

#### Steps:

• First, ask the user to enter a number.
• create a function in which, with each recursion, we decrease the number value by one.
• And add the decremented number with the actual number itself.

### Python Program to Find Sum of Natural Numbers Using Recursion

Python Code

``````def first_sum(n):
if n <= 1:
return n
else:
#recursion
return n + first_sum(n-1)

num = int(input("Enter the Number: "))

if num > 0:
print("The sum of first", num, "is ",first_sum(num))
else:

Output 1:

``````Enter the Number: 18
The sum of first 18 is 171``````

Output 2:

``````Enter the Number: 4
The sum of first 4 is 10``````