BB(8)

The 8-state, 2-symbol busy beaver problem BB(8) is unsolved and largely unexplored. It is assumed that the longest running machine will almost certainly run for more than Graham's number steps. The current champion is the BB(7) champion 1RB0RA_1LC1LF_1RD0LB_1RA1LE_1RZ0LC_1RG1LD_0RG0RF (bbch) by default.

An enumeration of a test sample of BB(8) TMs in Nov 2025 has shown this domain to be even harder to enumerate than BB(2,7).