n | a(n) |
---|---|
1 | 1 |
2 | 3 |
3 | 9 |
4 | 99 |
5 | 9999 |
6 | 99999999 |
7 | 9999999999999999 |
8 | 99999999999999999999999999999999 |
9 | 9999999999999999999999999999999999999999999999999999999999999999 |
[1,3,9,99,9999,99999999,9999999999999999, 99999999999999999999999999999999, 99999999999999999999999999999999999999999999999999\ 99999999999999] |