(letrec ((factorial (λ (n)
                      (if (zero? n)
                          1
                          (* n (factorial (- n 1)))))))
  (letrec ((sum-of-factorials
            (λ (n)
              (if (zero? n)
                  0
                  (+ (factorial n) (sum-of-factorials (- n 1)))))))
    (+ 2 (sum-of-factorials 5))))