C# Prime Factorisation

public static int[] Factorise(params int[] input)
{
    List<int> output = new List<int>();
    bool performedAny = false;

    for (int i = 0; i < input.Length; i++)
    {
        int number = Math.Abs(input[i]);
        bool performedThis = false;

        for (int j = number - 1; j > 1; j--)
        {
            if (number % j == 0)
            {
                output.Add(j);
                output.Add(number / j);

                performedThis = true;
                performedAny = true;

                break;
            }
        }

        if (!performedThis)
        {
            output.Add(number);
        }
    }

    output.Sort();
    int[] outArray = output.ToArray();

    if (input.Length > 0 && input[0] < 0)
    {
        outArray[0] = -outArray[0];
    }

    return performedAny ? Factorise(outArray) : outArray;
}