PrimesCustom.cs

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

namespace Primes
{
    class Program
    {
        static void Main()
        {
            int startNum = int.Parse(Console.ReadLine());
            int endNum = int.Parse(Console.ReadLine());
            List<int> primes = Enumerable.Range(0, endNum + 1).ToList();
            for (int i = 2; i <= Math.Sqrt(endNum); i++)
            {
                for (int j = i + i; j < endNum; j += i)
                {
                    primes[j] = -1;
                }
            }

            primes.RemoveAll(num => num < 2 || num == -1 || num < startNum);
            Console.WriteLine("Primes in range ({0} - {1}): {2}", startNum, endNum, string.Join(", ", primes));
            Console.WriteLine("Number of primes: {0}", primes.Count);
            Console.WriteLine("Sum of found primes: {0}", primes.Sum());
            Console.WriteLine("Primes ending with 1: {0}", primes.Count(n => n % 10 == 1));
            Console.WriteLine("Primes ending with 3: {0}", primes.Count(n => n % 10 == 3));
            Console.WriteLine("Primes ending with 7: {0}", primes.Count(n => n % 10 == 7));
            Console.WriteLine("Primes ending with 9: {0}", primes.Count(n => n % 10 == 9));
        }
    }
}