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Challenge goal
There remain 0 machine with 5 states to decide!! 🥳
We have reached our goal of proving "BB(5) = 47,176,870":
Here's what's next:
  • We are writing a human-readable paper presenting the BB(5) proof
  • We are working on new busy beaver values such as BB(6) and setting new goals for these
  • We are maintaining busy beaver knowledge through our Discord, forum and wiki
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What is this?
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Visualization:
Machine
1LH1LA_1LI1RG_0RD1LC_0RF1RE_1LJ0RF_1RB1RF_0LC1LH_0LC0LA_1LK1LJ_1RZ0LI_0LD1LE
Status: Decided (Halt)
Decider: Coq-BB5 âž•
Machine code:
01
A 1LH1LA
B 1LI1RG
C 0RD1LC
D 0RF1RE
E 1LJ0RF
F 1RB1RF
G 0LC1LH
H 0LC0LA
I 1LK1LJ
J 1RZ0LI
K 0LD1LE
Std format: 1LH1LA_1LI1RG_0RD1LC_0RF1RE_1LJ0RF_1RB1RF_0LC1LH_0LC0LA_1LK1LJ_1RZ0LI_0LD1LE
Copy code for https://turingmachine.io/
View at https://fiery.pages.dev/turing/
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Zoology
This zoology is collaborative.
1. Cyclers
e.g: #279,081 #4,231,819 #4,239,083 
2. Translated cyclers
e.g: #59,645,887 #15,167,997 #59,090,563 #63,687,188 
3. Bouncers
e.g: #80,747,967 #88,427,177 #5,228,688 #5,608,043 
4. Exponential counters
e.g: #11,004,366 #10,936,909 #3,840,180 
5. Bells
e.g: #8,527,536 #73,261,028 #63,938,734 
Not classified yet:
e.g: #4,446,642 #7,410,754 #43,374,927 
Highlighted machines
Interesting machines:
· "inverted counter" [bbchallenge, 2023]
· "helix" [bbchallenge, 2023]
· "pointy wide" [bbchallenge, 2023]
· "chaotic" [Marxen & Buntrock, 1990]
· "complex counter" [Marxen & Buntrock, 1990]
· Machine #7,410,754
· Machine #2,977,651
· Machine #9,005,190
· Machine #43,374,927
· Machine #14,263,231
· Machine #36,909,813
BB champions and other halting machines:
· 2,133,492-halter [bbchallenge, 2021]
· 23,554,764-halter [bbchallenge, 2021]
· BB(5): 47,176,870-halter [Marxen & Buntrock, 1990]
· BB(6): >2↑↑↑5> 2\uparrow\uparrow\uparrow 5-halter [mxdys, 2025]
Some Skelet's machines:
· Skelet's machine 1 ≈ Machine #68,329,601
· Skelet's machine 17 ≈ Machine #1,365,166
· full list