User blog comment:Simplicityaboveall/Insanely Fast-Growing Functions/@comment-1605058-20170915175750/@comment-25601061-20170915220938

H(x) has growth rate ω2

g1(x) has growth rate ω2+1

gy(x) has growth rate ω2+y

G(x) has growth rate ω3

G+(x) has growth rate ω3+1

However, [1@x/y], if it was well defined, would have growth rate ψ(Ωω) (but it could go much further, depends on the level of nestings)