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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 11 |
| 2 | 91 |
| 3 | 1001 |
| 4 | 11011 |
| 5 | 91091 |
| 6 | 999001 |
| 7 | 10989011 |
| 8 | 90909091 |
| 9 | 1000000001 |
| 10 | 11000000011 |
| 11 | 91000000091 |
| 12 | 1001000001001 |
| 13 | 11011000011011 |
| 14 | 91091000091091 |
| 15 | 999001000999001 |
| 16 | 10989011010989011 |
| 17 | 90909091090909091 |
| 18 | 999999999000000001 |
[1,11,91,1001,11011,91091,999001,10989011, 90909091,1000000001,11000000011,91000000091, 1001000001001,11011000011011,91091000091091, 999001000999001,10989011010989011, 90909091090909091,999999999000000001] |