using System;

using System.Linq;

​

public class Program

{

    private static string ToStr(int index) 

    {

        Console.WriteLine(index);

        return "A" + index;

    }

​

    public static void Main()

    {

        var ss = Enumerable.Range(0, 10).Select(ToStr);

        foreach(var s in ss.Skip(5).Take(5))

        {

            Console.WriteLine(s);

        }

    }

}