static void Main(string[] args)
{
ArithmeticProgression AP = new ArithmeticProgression();
Debug.WriteLine(AP.GetAverage());
Debug.WriteLine(AP.GetSum());
}
static void Main(string[] args)
{
ArithmeticProgression a = new ArithmeticProgression(2, 3);
Console.WriteLine(a.SumOfNMembers(5));
Console.ReadKey();
}