1,5,21,85(?)
问题描述：
1,5,21,85(?)
答
5=1X4+1;
21=5x4+1;
85=21x4+1;
答案是341=85x4+1.
1,5,21,85(?)
5=1X4+1;
21=5x4+1;
85=21x4+1;
答案是341=85x4+1.