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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 121 |
| 5 | 10201 |
| 6 | 12321 |
| 7 | 1002001 |
| 8 | 100020001 |
| 9 | 102030201 |
| 10 | 10000200001 |
| 11 | 1000002000001 |
| 12 | 1002003002001 |
| 13 | 100000020000001 |
| 14 | 10000000200000001 |
| 15 | 10002000300020001 |
| 16 | 1000000002000000001 |
| 17 | 100000000020000000001 |
| 18 | 100002000030000200001 |
[1,4,9,121,10201,12321,1002001,100020001, 102030201,10000200001,1000002000001,1002003002001, 100000020000001,10000000200000001, 10002000300020001,1000000002000000001, 100000000020000000001,100002000030000200001] |