The house number of Xiaohong’s house is a five-digit number, the highest digit is 3, the lowest digit is 4, the tens digit is twice the unit digit, and the other numbers are all 0. What is the house number of her house?
小红家的门牌号是个五位数，最高位数字是3，最低位数字是4，十位数字是个位数字的两倍，其他数字都是0，她家的门牌号是多少．
<result>30_084</result>