That means a lot VA. I would have been putting this much work into it whether or not other people were too but I'm glad I'm not just talking to myself here.
He said the thing about colours being part of the key before he posted anything about colours, so I only just noticed it a couple days ago. I don't think anyone's looked at this yet. So it might mean we use the -f column to find 2d(n-1) and use d^2 in (0,n), or something like that.
We don't seem to have even found all that much about (an)(a(n-1)) yet to begin with, so I'm just thinking over ideas.