Python Program to Find Sum of Natural Numbers Using Recursion

By | October 3, 2021
Python Program to Find Sum of Natural Numbers Using Recursion

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 topics to create this program.

  • 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

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:
    print("Please Enter a valid number")

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

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Author: Vinay

I am a Full Stack Developer with a Bachelor's Degree in Computer Science, who also loves to write technical articles that can help fellow developers.

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