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| n | a(n) |
|---|---|
| 1 | 1999 |
| 2 | 9199 |
| 3 | 338383 |
| 4 | 383833 |
| 5 | 1181881 |
| 6 | 1881181 |
| 7 | 1881811 |
| 8 | 2222929 |
| 9 | 2922229 |
| 10 | 8118181 |
| 11 | 8188111 |
| 12 | 8881111 |
| 13 | 9222229 |
| 14 | 15551551 |
| 15 | 15555151 |
| 16 | 15555511 |
| 17 | 16166611 |
| 18 | 16616161 |
| 19 | 33333373 |
| 20 | 33733333 |
| 21 | 34434343 |
| 22 | 44334343 |
| 23 | 44343433 |
| 24 | 51155551 |
| 25 | 51515551 |
| 26 | 55155151 |
| 27 | 55155511 |
| 28 | 55515151 |
[1999,9199,338383,383833,1181881,1881181,1881811, 2222929,2922229,8118181,8188111,8881111,9222229, 15551551,15555151,15555511,16166611,16616161, 33333373,33733333,34434343,44334343,44343433, 51155551,51515551,55155151,55155511,55515151] |