Busy Beaver and Collatz

One interesting result we know of is that these parity sequences are not Sturmian due to:

Dubickas A. On Integer Sequences Generated by Linear Maps. Glasgow Mathematical Journal . 2009; 51(2): 243-252. doi:10.1017/S0017089508004655

AFAICT, Sturmian sequences are basically sequences that aren’t periodic, but “almost” are.