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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 99 |
| 3 | 909 |
| 4 | 939 |
| 5 | 949 |
| 6 | 959 |
| 7 | 969 |
| 8 | 979 |
| 9 | 989 |
| 10 | 999 |
| 11 | 9009 |
| 12 | 9119 |
| 13 | 9229 |
| 14 | 9339 |
| 15 | 9449 |
| 16 | 9559 |
| 17 | 9669 |
| 18 | 9779 |
| 19 | 9889 |
| 20 | 9999 |
| 21 | 90009 |
| 22 | 90109 |
| 23 | 90209 |
| 24 | 90309 |
| 25 | 90409 |
| 26 | 90509 |
| 27 | 90609 |
| 28 | 90809 |
| 29 | 90909 |
| 30 | 91119 |
| 31 | 91219 |
| 32 | 91319 |
| 33 | 91419 |
| 34 | 91519 |
| 35 | 91619 |
| 36 | 91719 |
| 37 | 91819 |
| 38 | 91919 |
| 39 | 92029 |
| 40 | 92129 |
| 41 | 92229 |
| 42 | 92329 |
[9,99,909,939,949,959,969,979,989,999,9009,9119, 9229,9339,9449,9559,9669,9779,9889,9999,90009, 90109,90209,90309,90409,90509,90609,90809,90909, 91119,91219,91319,91419,91519,91619,91719,91819, 91919,92029,92129,92229,92329] |