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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 99 |
| 3 | 891 |
| 4 | 9999 |
| 5 | 89991 |
| 6 | 989901 |
| 7 | 8909109 |
| 8 | 99999999 |
| 9 | 899999991 |
| 10 | 9899999901 |
| 11 | 89099999109 |
| 12 | 999899990001 |
| 13 | 8999099910009 |
| 14 | 98990099010099 |
| 15 | 890910891090891 |
| 16 | 9999999999999999 |
| 17 | 89999999999999991 |
| 18 | 989999999999999901 |
[1,9,99,891,9999,89991,989901,8909109,99999999, 899999991,9899999901,89099999109,999899990001, 8999099910009,98990099010099,890910891090891, 9999999999999999,89999999999999991, 989999999999999901] |