1,
2,
3,
6,
9,
10,
11,
12,
13,
15,
17,
20
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
:low_num - :high_num of :total_num
:num of :total_num
