A386909 Iterates of g(x), starting at x = 0 until g(x) == 2 (mod 3), where g(x) = (5*x + 18)/3 if x == 0 (mod 3) and g(x) = (5*x + 22)/3 if x == 1 (mod 3).

0, 6, 16, 34, 64, 114, 196, 334, 564, 946, 1584, 2646, 4416, 7366, 12284

Offset: 0

Author

Paolo Xausa, Aug 07 2025

Keywords

• nonn
• fini
• full
• easy

Comments

These iterates correspond to the computation carried out by the 5-state Marxen-Buntrock Turing machine, which halts after 47176870 = BB(5) = A060843(5) steps (see Aaronson link).

Links

• Scott Aaronson, BusyBeaver(5) is now known to be 47,176,870, Shtetl-Optimized, 2024.
• Wikipedia, Busy beaver.
• Index entries for sequences related to Busy Beaver problem

Crossrefs

Cf. A060843.

Programs

Mathematica

NestWhileList[(5*# + If[Mod[#, 3] == 0, 18, 22])/3 &, 0, Mod[#, 3] < 2 &]