User blog comment:TechKon/Sponge's Graham Generator/@comment-25601061-20150806230646

I should have defined levels as you did, a long time ago.

Anyways, an extension.

Gn(((...(((m)))...))) (x parentheses) = m representing the amount of recursive procedures minus one (replacing Gn with Gn(((...(((n)))...))) (x-1 parentheses)), having each ending amount being Gn(((...(((m-1)))...))) (x parentheses).

I believe it's growth rate is fω2(n)