using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var list = Enumerable.Range(0,24)

            .Where(a => a%2 == 0)

            .ToList();

        var eq24 = SubSetsOf(list).Where(x=> x.Sum() == 24).ToList(); 

        Console.WriteLine(eq24.Count);

        foreach(var item in eq24)

            Console.WriteLine(string.Join(", ", item));

    }

    public static IEnumerable<IEnumerable<T>> SubSetsOf<T>(IEnumerable<T> source)

    {

        if (!source.Any())

            return Enumerable.Repeat(Enumerable.Empty<T>(), 1);

​

        var element = source.Take(1);

​

        var haveNots = SubSetsOf(source.Skip(1));

        var haves = haveNots.Select(set => element.Concat(set));

​

        return haves.Concat(haveNots);

    }

}