This edition of TMBR is in progress and has not yet been released. Please add any notes you think may be relevant (including in the form a of a TODO with a link to any relevant Discord discussion).
TODO. Write a summary of what happened during BB(3,3) month (October) and BB(2,5) month (November).
Misc
Discord user Vonhust made a Macro Machine achieving 2 billion steps / s, and is planning even more optimalizations. TODO: Sources, details, graph.
BB Adjacent
All Fractran deciders summarized and their relations, shared by Daniel Yuan on 14 Nov 2025Busy Beaver for Fractan, or BBf was introduced on 1 Nov by Jason Yuen, who also solved the first 14 values. Then, all values up to 19 were solved, with 19 requiring 3 programs to be proven by hand. For n = 20, 34 holdouts remain, while for n = 21, 587 holdouts are remaining. Three BB-Cryptids were also transformed into Fractran programs, so we know that n = 29 requires solving Hydra.
Cyclic Tag was introduced by Discord user Jack on 14 Nov. The first two values, n = 1 and 2 were also solved by him. Then, lower bounds were given for values up to n = 7. CTBB(7) reaches hexation.
The code provided by mxdys breaks up the BB(2,7) enumeration into 1 million subtasks which each run for ~10 minutes and leave ~2500 holdouts based on an average of the first 1K subtasks. These values are about 5 times longer than and 25 times larger than the ones for BB(7).
Terry Ligocki enumerated the first 2 subtasks, resulting in 62,062,284 holdouts, which can be found here.
The expected number of holdouts after the enumeration is ~2'500'000'000.
