View Code of Problem 48

import java.util.Scanner;


public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        double result = 0;
        for (int i = 0; i < n; i++) {
            result = result + (fib(2,3,i+1) / fib(1,2,i+1));
        }
        System.out.println(String.format("%.6f", result));
    }

    private static double fib(int t1, int t2, int index) {

        if (index == 1) {
            return t1;
        } else if (index == 2) {
            return t2;
        }else {
            return fib(t1, t2, index - 1) + fib(t1, t2, index - 2);
        }

    }
}