MBN, or Miner's Bracket Enumeration, was inspired by BEAF and weaker than it, but can produce big numbers.
If you take [4, 3, 9], you do:
. And if you take [8, 3, 77, 14, 19], than it will be
. But you can't create big numbers easily, as Graham's Number would be
And if you understand the pattern, you understood the function!