What number comes next in following series 9,12,21,48

What number comes next in following series 9,12,21,48 奥英难题,1.What number comes next in the following series?9,12,2 what number comes next in the following series? 1.单项选择What number come next in the following series（系列）?9,12 What would be the next number in the following series?(在下面这组 What group of letters comes next in this series? What number comes next What number comes next in this sequence:_______________ 9174 what would be the next number in this series"2...4...8...16. which number should come next in this series? 一道英语的智力题求解What would be the next number in this series?0,5,1 What number comes next?1 11 21 1211 111221 312211 13112221 _