; thue-morse sequence

(define (complement digits)
  (map (lambda (d) (if (zero? d) 1 0)) digits))

(define (thue-morse n)
  (let loop ((tms '(0)) (n n))
    (if (zero? n) tms
      (loop (append tms (complement tms)) (- n 1)))))

(display (thue-morse 6))

(0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0)