0 1
1 01
2 001
3 0001
4 00001
5 000001
6 0000001
7 00000001
8 000000001
9 0000000001
10 00000000001
11 000000000001
12 0000000000001
13 00000000000001
14 000000000000001
15 0000000000000001
