BB(4,3) > 2↑↑↑(2^2^32)

[Shawn Ligocki]

The TM 0RB1RZ0RB_1RC1LB2LB_1LB2RD1LC_1RA2RC0LD was found by Pavel Kropitz back in May 2024 along with a list of 6 other long running machines (See "Potential Champions" on BB(4,3)). Last month, Racheline analyzed it on the bbchallenge Discord and the resulting analysis is available on 0RB1RZ0RB_1RC1LB2LB_1LB2RD1LC_1RA2RC0LD. She concludes that it halts with exactly 5*2^(2^(f^{g^n1(n0)}(0)+1)+2)+7 non-zero symbols on the tape where 

f(n) = 2^2^(n+1)
g(n) = (5*2^(2^(f^n(0)+1)+2)-8)/9
n0 = (5*2^(2^(2^32+1)+1)-4)/9
n1 = 2^(2^32+1)-4

I haven't had a chance to look over the machine myself, but wanted to share it here so others had an opportunity to check it out.