5-state busy beaver winner: Difference between revisions

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{{machine|1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA}}
{{machine|1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA}}
The 5-state busy beaver champion (and winner!) is: [https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA&status=halt https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA]. The machine halts after 47,176,870 steps. It was found by Heiner Marxen and Jürgen Buntrock in 1989<ref>H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html</ref>.
The 5-state busy beaver champion (and winner!) is: [https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA&status=halt https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA]. It was found by Heiner Marxen and Jürgen Buntrock in 1989<ref>H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html</ref>. The machine halts after 47,176,870 steps and with 4098 1's on the tape, showing that <math>BB(5) \ge 47,176,870</math> and <math>\Sigma(5) \ge 4098</math>.
 
This machine repeatedly applies the following map, starting with <math>x = 0</math><ref>Aaronson, S. (2020). The Busy Beaver Frontier. Page 10-11. https://www.scottaaronson.com/papers/bb.pdf</ref>:
<math display="block">\begin{align}
  g(x) & \to g\left(\frac{5x+18}{3}\right) && \text{if }x \equiv 0 \pmod{3} \\
  g(x) & \to g\left(\frac{5x+22}{3}\right) && \text{if }x \equiv 1 \pmod{3} \\
  g(x) & \to \text{HALT}                  && \text{if }x \equiv 2 \pmod{3}
\end{align}</math>
 
The full orbit from <math>x = 0</math> is:
<math display="block">\begin{array}{l}
  0    & \to & 6    & \to & 16  & \to & 34  & \to & 64    & \to & \\
  114  & \to & 196  & \to & 334  & \to & 564  & \to & 946  & \to & \\
  1584 & \to & 2646 & \to & 4416 & \to & 7366 & \to & 12284 & \to & \text{HALT}
\end{array}</math>

Revision as of 20:50, 4 July 2024

The 5-state busy beaver champion (and winner!) is: https://bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA. It was found by Heiner Marxen and Jürgen Buntrock in 1989[1]. The machine halts after 47,176,870 steps and with 4098 1's on the tape, showing that and .

This machine repeatedly applies the following map, starting with [2]:

The full orbit from is:

  1. H. Marxen and J. Buntrock. Attacking the Busy Beaver 5. Bulletin of the EATCS, 40, pages 247-251, February 1990. https://turbotm.de/~heiner/BB/mabu90.html
  2. Aaronson, S. (2020). The Busy Beaver Frontier. Page 10-11. https://www.scottaaronson.com/papers/bb.pdf