It is unclear
I wasn't one of the voters, but given the current question state I would also vote to close as unclear.
I've read the challenge description several times and I still don't know what it's asking for. Part of that is the challenge description, which consists only of the first paragraph, is all one run-on sentence. Breaking that out into bullet points could help, or restructuring it to be more than one sentence.
Secondly, I don't think that "Do not use standard library functions for permutations or combinatorics." is a good fit for the challenge. Depending upon the language, there is a lot of grey area where arguing semantics can come into play. This is a non-observable requirement, and is one of the things to avoid when writing good challenges.
Finally, I'm not convinced that the boundaries of the challenge (up to
123456789, if I'm understanding correctly) will provide a challenging enough scenario to allow for fastest-code. I believe that submissions will likely run into ceilings surrounding startup/shutdown code variations rather than providing enough variations in timing of the actual algorithm. This will either make the challenge less language-agnostic, or will cause submissions to be all within margin of error.