; multiplicative persistance
 
(define (digits n . args)
  (let ((b (if (null? args) 10 (car args))))
    (let loop ((n n) (d '()))
      (if (zero? n) d
          (loop (quotient n b)
                (cons (modulo n b) d))))))
 
(define (uniq-c eql? xs)
  (if (null? xs) xs
    (let loop ((xs (cdr xs)) (prev (car xs)) (k 1) (result '()))
      (cond ((null? xs) (reverse (cons (cons prev k) result)))
            ((eql? (car xs) prev) (loop (cdr xs) prev (+ k 1) result))
            (else (loop (cdr xs) (car xs) 1 (cons (cons prev k) result)))))))
 
(define (per n)
  (let loop ((n n) (xs (list)))
    (if (< n 10)
        (cons n xs)
        (loop (apply * (digits n))
              (cons n xs)))))
 
(display (per 327)) (newline)

OyBtdWx0aXBsaWNhdGl2ZSBwZXJzaXN0YW5jZQoKKGRlZmluZSAoZGlnaXRzIG4gLiBhcmdzKQogIChsZXQgKChiIChpZiAobnVsbD8gYXJncykgMTAgKGNhciBhcmdzKSkpKQogICAgKGxldCBsb29wICgobiBuKSAoZCAnKCkpKQogICAgICAoaWYgKHplcm8/IG4pIGQKICAgICAgICAgIChsb29wIChxdW90aWVudCBuIGIpCiAgICAgICAgICAgICAgICAoY29ucyAobW9kdWxvIG4gYikgZCkpKSkpKQoKKGRlZmluZSAodW5pcS1jIGVxbD8geHMpCiAgKGlmIChudWxsPyB4cykgeHMKICAgIChsZXQgbG9vcCAoKHhzIChjZHIgeHMpKSAocHJldiAoY2FyIHhzKSkgKGsgMSkgKHJlc3VsdCAnKCkpKQogICAgICAoY29uZCAoKG51bGw/IHhzKSAocmV2ZXJzZSAoY29ucyAoY29ucyBwcmV2IGspIHJlc3VsdCkpKQogICAgICAgICAgICAoKGVxbD8gKGNhciB4cykgcHJldikgKGxvb3AgKGNkciB4cykgcHJldiAoKyBrIDEpIHJlc3VsdCkpCiAgICAgICAgICAgIChlbHNlIChsb29wIChjZHIgeHMpIChjYXIgeHMpIDEgKGNvbnMgKGNvbnMgcHJldiBrKSByZXN1bHQpKSkpKSkpCgooZGVmaW5lIChwZXIgbikKICAobGV0IGxvb3AgKChuIG4pICh4cyAobGlzdCkpKQogICAgKGlmICg8IG4gMTApCiAgICAgICAgKGNvbnMgbiB4cykKICAgICAgICAobG9vcCAoYXBwbHkgKiAoZGlnaXRzIG4pKQogICAgICAgICAgICAgIChjb25zIG4geHMpKSkpKQoKKGRpc3BsYXkgKHBlciAzMjcpKSAobmV3bGluZSk=