code: func doLinksPage(w http.ResponseWriter, r *http.Request, n int, offset int) {
  	w.Header().Add("Content-Type", htmlContentType)
  	w.WriteHeader(http.StatusOK)
  
  	w.Write([]byte("<html><head><title>Links</title></head><body>"))
  	for i := 0; i < n; i++ {
  		if i == offset {
  			fmt.Fprintf(w, "%d ", i)
  		} else {
  			fmt.Fprintf(w, `<a href="/links/%d/%d">%d</a> `, n, i, i)
  		}
  	}
  	w.Write([]byte("</body></html>"))
  }
docs: // doLinksPage renders a page with a series of N links