c#编程：有一个分数序列，2/1，3/2，5/3，8/5，13/8，21/13....找出数列的规律并求出其前30项的和

using System;using System.Collections.Generic;using System.Linq;using System.Text;//有一个分数序列，2/1，3/2，5/3，8/5，13/8，21/13....找出数列的规律并求出其前30项的和namespace ans1{    class Program    {        static void Main(string[] args)        {            double sum = 0;            double tn = 0;            int temp;            int i = 1, j = 2;            int k;            for (k = 1; k <= 30; k++)            {                tn = j/(i*1.0);                temp = j;                j = i + j;                i = temp ;                               sum = sum + tn;            }            Console.WriteLine("{0}",sum);        }    }}