BB(2,3): Difference between revisions

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== Champions ==
== Champions ==
S(2,3) = 38 and Σ(2,3) = 9 and both are achieved by only one champion (in [[TNF]]):
S(2,3) = 38 and Σ(2,3) = 9 and both are achieved by only one [[Champions#3-Symbol TMs|champion]] (in [[TNF]]):
* {{TM|1RB2LB1RZ_2LA2RB1LB|halt}}
* {{TM|1RB2LB1RZ_2LA2RB1LB|halt}}



Latest revision as of 10:41, 11 August 2025

BB(2,3) refers to the Busy Beaver function with 2 states and 3 symbols. The value was discovered by Brady in 1988 (and independently by Michel in 2004) and proven by Lafitte and Papazian in 2007.

Champions

S(2,3) = 38 and Σ(2,3) = 9 and both are achieved by only one champion (in TNF):

  • 1RB2LB1RZ_2LA2RB1LB (bbch)

Enumeration

The top 20 longest running BB(2,3) TMs (in TNF-1RB) are:

Standard Format     Steps Σ
1RB2LB1RZ_2LA2RB1LB    38 9
1RB0LB1RZ_2LA1RB1RA    29 8
1RB2LA1RZ_1LB1LA0RA    26 6
1RB1LA1LB_0LA2RA1RZ    26 6
1RB1LB1RZ_2LA2RB1LB    24 7
1RB2LA1RZ_0LB1LA0RA    22 4
1RB2RB1RZ_1LB1RA0LA    21 4
1RB2LA2RB_1LA1RZ1RA    20 6
1RB2LA1RZ_2LA2RB1LB    20 6
1RB2LA0RB_1LA1RZ1RA    20 5
1RB0LB1RZ_2LA2LB1RA    19 7
1RB0RB1RZ_1LB2RA1LA    19 6
1RB2LB1LA_2LA1RZ2RB    18 7
1RB1LB2LA_1LA2RB1RZ    18 7
1RB2LB2LA_2LA1RZ0RA    18 6
1RB2LA1RZ_1LB1RA2RB    18 6
1RB2LB1RZ_2LA1RA0LB    18 5
1RB0RB1RZ_1LB2LA2RA    17 6
1RB2LB0LB_2LA1RZ2RB    17 4
1RB2RA1RZ_0LB2RB1LA    17 3

For the full list of 866 halting BB(2,3) TMs, see: https://github.com/sligocki/busy-beaver/blob/main/Machines/bb/2x3.txt