Python Program to Display Fibonacci Sequence Using Recursion

We are given a task to write the Fibonacci sequence using recursion. we will take the range as input of integer and then print the Fibonacci Sequence. In this article, we will see the method of Python Program to Display Fibonacci Sequence Using Recursion.

Example:

Input: n = 9
Output: 0 1 1 2 3 5 8 13 21
Explanation: Here, we have n = 9, and we print the 
Fibonacci Sequence by adding one element with its 
subsequent element.

What is the Fibonacci Sequence?

The Fibonacci sequence is like a mathematical melody, where each number dances to the rhythm of the two preceding ones. It usually begins its graceful dance with the numbers 0 and 1. This sequence is not just a mere mathematical curiosity; it's like a versatile performer that appears on the stages of various mathematical and computer science domains. The Fibonacci sequence is defined by the recurrence relation:

F(n) = F(n-1) + F(n-2)

where ( 0 ) = 0 F(0)=0 and ( 1 ) = 1 F(1)=1.

Python Program to Display Fibonacci Sequence Using Recursion

Below, are the implementation of Python Program to Display Fibonacci Sequence Using Recursion.

• The code defines a recursive function, fib, to generate Fibonacci series.
• It also contains a function print_fib to handle edge cases and initiate the Fibonacci series printing.
• The program checks for invalid inputs and prints appropriate messages.
• It initializes the series with 0 and 1 and calculates subsequent terms by summing the previous two.
• The driver code calls print_fib with the desired number of Fibonacci series terms, which is set to 9 in this case.

Implementation

# Recursive function to print the Fibonacci series
def fib(n, prev1, prev2):
    if n < 3:
        return
    fn = prev1 + prev2
    prev2 = prev1
    prev1 = fn
    print(fn, end=" ")
    fib(n - 1, prev1, prev2)

def print_fib(n):
    # When the number of terms is less than 1
    if n < 1:
        print("Invalid number of terms")
    elif n == 1:
        print(0)
    elif n == 2:
        print("0 1")
    else:
        print("0 1", end=" ")
        fib(n, 1, 0)

# Driver code
if __name__ == "__main__":
    n = 9
    # Function call
    print_fib(n)

0 1 1 2 3 5 8 13 21 

Time complexity: O(n),
Auxiliary Space: O(n),