Two things.
f^i(x) is the standard f(f(f(f(...(f(x))...).
f^^2(x) is f^{f(x)}(x), and f^^3(x) is f^{f^{f(x)}(x)}(x).
f^^^2(x) is f^{f^{f^{f^{f^{......{f^(x)}(x)}.....(x)}(x).
Extend as normal knuth up arrow.
Now, we define d64 as g64, but every 3 before arrows is replaced with the busy beaver function and every 3 after the arrows is replaced with "(3)".
I have made a C++ program to expand a 3-element thoop into a bunch of nested 2-element thoops:
Code: Select all
[[2, [2, 2, [[[3, [3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, 1]+2, [[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 3, 1]+2, 1]+2, 1]+4]+3, [2, [[[3, [3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, 1]+2, [[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 3, 1]+2, 1]+2, 1]+4, 2]+3]+3, [[2, 2, [[[3, [3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, 1]+2, [[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 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2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 3, 1]+2, 1]+2, 1]+4, 2, 2]+3]+3, [[2, [[[3, [3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, 1]+2, [[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 3, 1]+2, 1]+2, 1]+4, 2]+3, [[[[3, [3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, 1]+2, [[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, 1]+2, [[[3, [[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 1]+2, [[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 1]+2, [[[[[[4, [3, [2, [2, 2]+3]+3]+3]+3, [[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3]+3, [[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3]+3, [[[[3, [2, [2, 2]+3]+3]+3, [[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3]+3, [[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3]+3, [[[[2, [2, 2]+3]+3, [[2, 2]+3, 2]+3]+3, [[[2, 2]+3, 2]+3, 3]+3]+3, [[[[2, 2]+3, 2]+3, 3]+3, 4]+3]+3]+3]+4, 3, 1]+2, 3, 1]+2, 1]+2, 1]+4, 2, 2]+3, 2]+3]+2
and hence [1,1,1,1] is around G(14) or G(15).
The expansion of [3,3,3] has not finished yet, and the tree is expanding at 30K nodes; however, it is most likely no bigger than G(22).
This program has the ability (due to some weird property of this thoop) to estimate which number of Graham it is closest to before actually expanding the whole thoop out. Through this ability, I have found out:
So not that impressive compared to others e.g. Conway arrow notation. But this is only using F(a) = 1; it would grow much faster with different F(a).