1LB1LD_1RC---_1RE1RD_1LE0RC_1LA0LD

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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":

See the formal Coq proof
See the official announcement

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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Machine

1LB1LD_1RC---_1RE1RD_1LE0RC_1LA0LD

Equivalent ID: #9,914,965

Status: Decided (Non Halt)

Decider: Coq-BB5 ➕

Machine code:

	0	1
A	1LB	1LD
B	1RC	---
C	1RE	1RD
D	1LE	0RC
E	1LA	0LD

Std format: 1LB1LD_1RC---_1RE1RD_1LE0RC_1LA0LD

Equivalent machine: 1RB1RD_1LC---_1LE1LD_1RE0LC_1RA0RD

Equivalent ID: 9914965

Copy code for https://turingmachine.io/

View at https://fiery.pages.dev/turing/

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Deciders

Deciders are programs that automatically decide whether machines halt or not.
Here are the currently applied deciders:

1. Cyclers 2. Translated Cyclers 3. Backward Reasoning 4. Halting Segment 5. Finite Automata Reduction 6. Bouncers 7. Coq-BB5

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):

\simeq 10\uparrow\uparrow 15

-halter [Kropitz, 2022]

Some Skelet's machines:

· Skelet's machine 1 ≈ Machine #68,329,601

· Skelet's machine 17 ≈ Machine #1,365,166

· full list