A fibonacci series is a series of numbers that the next number is found by adding the two immediate preceded numbers of it. For example : 0, 1, 1, 2, 3, 5, 8, 13, 21 . . In this article, we are going to write a program to print first N numbers in fibonacci series. See below example.

 import java.util.Scanner;
class Fibonacci{  
    public static void main(String args[])  { 
	   System.out.println("Please Enter Number: ");
       Scanner read = new Scanner(System.in);
       int count = read.nextInt();
       int a1=0 , a2=1 , a3 ;    
       System.out.print(a1+" "+a2); //prints 0 and 1    
       for(int i=2;i < count;i++)
       {    
       a3=a1+a2;    
       System.out.print( " "+a3);    
       a1=a2;    
       a2=a3;    
       }      
      } 
} 

See below example to find Nth fibonacci number using mathematical formula. To find Nth fibonacci number mathematical formula is :

         (X^n - (1 - X)^n)/√5 . where    X = (1-√5 )/2

public class NthFibonacci{
	public static void main(String as[])
	{
		int number =20;
		double a = (1+Math.sqrt(5))/2;
		double b = (1-Math.sqrt(5))/2;
		double result = ( Math.pow(a,number)-Math.pow(b,number))/Math.sqrt(5);
		System.out.println(number +" th febinocci number is : "+(int)result;
	}
}

Due to int size restriction in java , we can find upto 47th fibonacci number only.

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