6.2Loops_PrintNumbersThatAreNotDivisibleBy3And7

using System;

class NotDivisible3And7All1ToNNumbers
{
    static void Main ()
    {
        Console.Write("Please, enter a whole positive number for N = ");
        string numberStr = Console.ReadLine();
        int numberN = int.Parse(numberStr);
        if (numberN < 1)
        {
            Console.WriteLine("Error - Invalid Number !!!");
        }
        else
        {
            Console.Write("The all numbers from 1 to that number N, wich not divisible"
        + " by 3 and 7 at the same time, are: ");
            for (int i = 1; i <= numberN; i++)
            {
                if ((i % (3 * 7)) != 0)
                {
                    Console.Write("{0} ", i);
                }
            }
        }
        Console.ReadLine();
    }
}