euler-transform.scm

(define (euler-transform s)
  (let ((s0 (stream-ref s 0))
	(s1 (stream-ref s 1))
	(s2 (stream-ref s 2))
	(s3 (stream-ref s 3)))
    (cons-stream
      (- s2 (/ (square (- s2 s1))
	       (+ s0 (* -2 s1) s2)))
      (euler-transform (stream-cdr s)))))