Python Program For Fibonacci Number Using Recurrsion

The Fibonacci numbers are the numbers in the following integer sequence.

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ……..

In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation..

 Fn = Fn-1 + Fn-2

with seed values

   F0 = 0 and F1 = 1.

# Function for nth Fibonacci number 

def Fibonacci(n): 
	if n<0: 
		print("Incorrect input") 
	# First Fibonacci number is 0 
	elif n==1: 
		return 0
	# Second Fibonacci number is 1 
	elif n==2: 
		return 1
	else: 
		return Fibonacci(n-1)+Fibonacci(n-2) 

# Call to function 

print(Fibonacci(9)) 

Output : 

21