5-state busy beaver winner: Difference between revisions

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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>:
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}
<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 \frac{5x+18}{3} && \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 \frac{5x+22}{3} && \text{if }x \equiv 1 \pmod{3} \\
   g(x) & \to \text{HALT}                   && \text{if }x \equiv 2 \pmod{3}
   g(x) & \to \text{HALT}     && \text{if }x \equiv 2 \pmod{3}
\end{align}</math>
\end{align}</math>



Revision as of 20:53, 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