Sumatoria de n numeros

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace modulo_Sumatoria
{
    class Program
    {
        static double sumatoria(double N)
        {
            double Suma = 0;
            for (int i = 1; i <= N; i++)
                Suma = (((i*i) + 1.0) / i)+Suma;
            return Suma;
        }

        static void Main(string[] args)
        {
            double n;
            //double aSuma;
            Console.WriteLine("Ingrese N : ");
            n = double.Parse(Console.ReadLine());

            //aSuma = sumatoria(n);
            Console.WriteLine("La sumatoria es :"+sumatoria(n));
            Console.ReadLine();


        }
    }
}