(Nils' Scheme Snippets)

(hyper integer₁ integer₂ integer₃) => integer

(hyper 4 3 3) => 7625597484987

(define (hyper n a b)
  (cond ((= n 0) (+ b 1))
        ((= n 1) (+ a b))
        ((= b 1) a)
        ((= n 2) (* a b))
        ((= n 3) (expt a b))
        ((= n 4) (expt a (hyper n a (- b 1))))
        ((> n 4) (hyper (- n 1) a (hyper n a (- b 1))))))