function findSequence(goal) {
  function find(start, history) {
    if (start == goal)
      return history;
    else if (start > goal)
      return null;
    else
      return find(start + 5, \"(\" + history + \" + 5)\") ||
             find(start * 3, \"(\" + history + \" * 3)\");
  }
  return find(1, \"1\");
}