Faster alternative to nested loops?

Question

I have a need to create a list of combinations of numbers. The numbers are quite small so I can use byte rather than int. However it requires many

Answer 1

var numbers = new[] { 2, 3, 4, 3, 4, 3, 3, 4, 2, 4, 4, 3, 4 };
var result = (numbers.Select(i => Enumerable.Range(0, i))).CartesianProduct();

Using the extension method at http://ericlippert.com/2010/06/28/computing-a-cartesian-product-with-linq/

public static IEnumerable> CartesianProduct(this IEnumerable> sequences)
{
    // base case: 
    IEnumerable> result =
        new[] { Enumerable.Empty() };
    foreach (var sequence in sequences)
    {
        // don't close over the loop variable (fixed in C# 5 BTW)
        var s = sequence;
        // recursive case: use SelectMany to build 
        // the new product out of the old one 
        result =
            from seq in result
            from item in s
            select seq.Concat(new[] { item });
    }
    return result;
}