User blog comment:Googleaarex/Stronger Hyperfactorial Array Notation/@comment-25418284-20131213221550/@comment-5029411-20131214132527

g(n) = f(f(...(f(f(n))...)) (n nested) = f^n(n)

h(n) = g(g(...(g(g(n))...)) (n nested) = g^n(n)

[1,2] = [...[1]...] (n nested)

5$[[0]2] = 5$[...[0]...] (5 nested)