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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 11 |
| 2 | 112 |
| 3 | 1122 |
| 4 | 11223 |
| 5 | 112233 |
| 6 | 1122334 |
| 7 | 11223344 |
| 8 | 112233445 |
| 9 | 1122334455 |
| 10 | 11223344556 |
| 11 | 112233445566 |
| 12 | 1122334455667 |
| 13 | 11223344556677 |
| 14 | 112233445566778 |
| 15 | 1122334455667788 |
| 16 | 11223344556677889 |
| 17 | 112233445566778899 |
| 18 | 1122334455667789000 |
| 19 | 11223344556677890010 |
| 20 | 112233445566778900111 |
| 21 | 1122334455667789001121 |
[1,11,112,1122,11223,112233,1122334,11223344, 112233445,1122334455,11223344556,112233445566, 1122334455667,11223344556677,112233445566778, 1122334455667788,11223344556677889, 112233445566778899,1122334455667789000, 11223344556677890010,112233445566778900111, 1122334455667789001121] |