using System;

using System.Diagnostics;

using System.Linq;

using System.Collections.Generic;

using System.Threading;

​

public class Program

{

    static bool isBlueMoon = false;

    public static void Main()

    {

        var sw = Stopwatch.StartNew();

        var multiples = GetMultiples(of: 23, count: 27_000_000).Where(q => q > 10).Take(15);

        if (isBlueMoon)

        {

            Console.WriteLine(String.Join(", ", multiples));

        }

​

        Console.WriteLine("Total elapsed seconds: " + sw.Elapsed.TotalSeconds);

    }

​

    private static IEnumerable<int> GetMultiples(int of, int count)

    {

        List<int> values = new();

        for (int i = 0; i < count; i++)

        {

            Thread.Sleep(100);

            yield return (i * of);

        }

    }

}