(defconstant GOLDEN-RATIO (/ (+ 1.0d0 (sqrt 5.0d0)) 2.0d0))

(defun Fibonacci ()
  "Print a table of representable Fibonacci sequence values.  Lisp
supports bignums, but we limit the output to values representable in
64-bit integers to make the output comparable to that from other
programming languages."
  (format t "~2D~A~25D~%" 1 #\Tab 1)
  (do* ((hi 1 (+ lo hi))
        (lo 1 (- hi lo))
        (n 2 (1+ n))
        (ratio #1=(float (/ hi lo) 1.0d0) #1#))
       ((>= hi #.(1- (expt 2 63))))
    (format t "~2D~A~25:D~A~19,15F~A~19,15F~%"
            n #\Tab hi #\Tab ratio #\Tab (- ratio GOLDEN-RATIO))))

(Fibonacci)