Deletable Primes Calculator - TizzyT

using System;
using System.Collections.Generic;
namespace DeletablePrimesCSharp
{
    class DelPrimes
    {
        static void Main(string[] args)
        {
            List<int> Primes = Sieve(10000000);
            bool[] Table = new bool[Primes[Primes.Count - 1] + 1];
            double sum = 17;
            foreach (int prime in Primes)
            {
                Table[prime] = true;
            }
            for (int i = 4; i <= Primes.Count - 1; i++)
            {
                if (i > Primes.Count - 1)
                    break;
                string intString = Convert.ToString(Primes[i]);
                Table[0] = false;
                for (int x = 0; x <= intString.Length - 1; x++)
                {
                    string crnt = intString.Remove(x, 1);
                    if (!(crnt.StartsWith("0")))
                    {
                        if (Table[int.Parse(crnt)] == true)
                        {
                            Table[0] = true;
                            break;
                        }
                    }
                }
                if (Table[0] == false)
                {
                    Table[Primes[i]] = false;
                    Primes.RemoveAt(i);
                    i--;
                }
                else
                {
                    sum += Primes[i];
                }
            }
            Console.WriteLine(Primes.Count + System.Environment.NewLine + sum);
            Console.ReadKey();
        }
        static List<int> Sieve(int limit)
        {
            List<int> Primes = new List<int> { 2, 3, 5, 7 };
            int sqrt = 0;
            int crntNbr = 11;
            while (crntNbr < limit)
            {
                sqrt = (int)Math.Sqrt(crntNbr);
                foreach (int prime in Primes)
                {
                    if (prime <= sqrt)
                    {
                        if (crntNbr % prime == 0)
                            break;
                    }
                    else
                    {
                        Primes.Add(crntNbr);
                        break;
                    }
                }
                crntNbr += 2;
            }
            return Primes;
        }
    }
}