# nth Fibonacci number in python

Hi, today we will learn how to find nth Fibonacci number in python. At first, we should know about what is the Fibonacci series.

## Find nth Fibonacci number in Python

**Fibonacci Series:**

Basically Fibonacci series is a series which follows a special sequence to store numbers.

**Rule:** **( 2nd previous number + 1st previous number ) = 3rd number ( Current number )**.

**Series:** **0, 1, 1, 2, 3, 5, 8, 13, 21, 34…….**

**Explanation**:

- 0 is the first number

Then series = 0 - 1 is the 2nd number

Then series = 0,1 ( after 1 the Fibonacci rule started ) - (0+1) = 1

Then series = 0,1,1 - (1+1) = 2

Then series = 0,1,1,2 - (1+2) = 3

Then series = 0,1,1,2,3 - (2+3) = 5

Then series = 0,1,1,2,3,5 - (3+5) = 8

Then series = 0,1,1,2,3,5,8 - (5+8) = 13

Then series = 0,1,1,2,3,5,8,13 - (8+13) = 21

Then series = 0,1,1,2,3,5,8,13,21 - (13+21) = 34

Then series = 0,1,1,2,3,5,8,13,21,34 and so on..

Here is the optimized and best way to print Fibonacci sequence: Fibonacci series in python (Time complexity:O(1))

## Get the nth number in Fibonacci series in python

This article covered how to create a Fibonacci series in python. This python program is very easy to understand how to create a Fibonacci series. After the creation of a Fibonacci series, we can find the nth Fibonacci number in the series.

**Code:**

n = int(input('Enter : ')) fibo_nums = [0,1] i=1 if(n==1 or n==2): print(n,'th Prime Number is :',fibo_nums[n-1]) print('Fibonacci Series :', fibo_nums) elif(n>2): while (True): fib = fibo_nums[i-1]+fibo_nums[i] fibo_nums.append(fib) if(len(fibo_nums)==n): break else: i+=1 print(n,'th Fibonacci Number is :', fibo_nums[n-1]) print('Fibonacci Series is :', fibo_nums) else: print('Please Enter A Valid Number')

**Output:**

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