一个数组：1,1,2,3,5,8,13,21...+m，求第30位数是多少？用递归实现；(常考！！！)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            if (n <= )
            {
                Console.WriteLine("必须大于0");
                return;
            }
            if (n == )  //时刻注意边界值！！！
            {
                Console.WriteLine("");
                return;
            }
            int[] data = new int[n];
            data[] = ;
            data[] = ;
            for (int i = ; i < n; i++)
            {
                data[i] = data[i - ] + data[i - ];
            }
            Console.WriteLine(data[n - ]);
 
            Console.ReadLine();
        }
    }
}