Python Program - Find Sum of Natural Numbers Using Recursion

Here's a Python program to find the sum of first n natural numbers using recursion:

def sum_natural_numbers(n):
    if n <= 0:
        return 0
    else:
        return n + sum_natural_numbers(n-1)

# Example usage
n = 5
sum = sum_natural_numbers(n)
print(f"Sum of first {n} natural numbers is {sum}")

Output:

Sum of first 5 natural numbers is 15

In the above program, sum_natural_numbers() is a recursive function that takes a positive integer n as input and returns the sum of first n natural numbers. If n is less than or equal to 0, the function returns 0. Otherwise, it calculates the sum of first n natural numbers by adding n with the sum of first n-1 natural numbers, which is calculated by calling the same function recursively with n-1 as the input. The base case for this recursive function is when n is less than or equal to 0.