Logic for getting fibonacci series?

static int Fibonacci (int x)
	{
	   Console.WriteLine ("Fibonacci = {0}", x);
	   if (x <= 1)
	   {
	      return x;
	   }
	   return Fibonacci (x-1) + Fibonacci (x-2);
	}
	      
	static void Main( )
	{
	   Console.WriteLine ("Fibonacci = {0}", Fibonacci (5));
	     
	   // Wait for read one key
	   Console.ReadKey();
	}