using Combinatorics.Collections;

using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main(string[] args)

    {

        int[] max_bounds = new int[] { 3, 3, 3 };

        foreach (int[] pattern in GetPatterns(max_bounds))

            Console.WriteLine(string.Join(null, pattern));

    }

​

    private static IEnumerable<int[]> GetPatterns(int[] maxBounds)

    {

        for (int i = 0; i <= maxBounds.Length; i++)

        {

            Combinations<int> combinations = new Combinations<int>(Enumerable.Range(0, maxBounds.Length), i, GenerateOption.WithoutRepetition);

            foreach (IReadOnlyList<int> combo in combinations)

            {

                int[] pattern = new int[maxBounds.Length];

                combo.ToList().ForEach(j => pattern[j] = 1);

                yield return pattern;

                int k = 0;

                while (k < combo.Count)

                {

                    if (pattern[combo[k]] < maxBounds[combo[k]])

                    {

                        pattern[combo[k]]++;

                        yield return pattern;

                        k = 0;

                        continue;

                    }

                    else

                        pattern[combo[k++]] = 1;

                }

            }

        }

    }

}