BB(3,4)

The current BB(3,4) champion is 1RB3LB1RZ2RA_2LC3RB1LC2RA_3RB1LB3LC2RC (bbch). It runs for $2\uparrow ^{15}5$ steps before halting. It was discovered by Pavel Kropitz in 2024 and was analysed by Shawn Ligocki in the same year.

Top Halters

The top 20 longest running halting BB(3,4) TMs are:

Standard format	(approximate) runtime
1RB3LB1RZ2RA_2LC3RB1LC2RA_3RB1LB3LC2RC (bbch)	$2\uparrow ^{15}5$