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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 121 |
| 5 | 10201 |
| 6 | 12321 |
| 7 | 114411 |
| 8 | 1002001 |
| 9 | 1234321 |
| 10 | 100020001 |
| 11 | 102030201 |
| 12 | 121242121 |
| 13 | 131141131 |
| 14 | 10000200001 |
| 15 | 10221412201 |
| 16 | 12102420121 |
| 17 | 131441144131 |
| 18 | 1000002000001 |
| 19 | 1002003002001 |
| 20 | 1020304030201 |
| 21 | 1143442443411 |
| 22 | 1210024200121 |
| 23 | 4133144413314 |
| 24 | 4342230322434 |
| 25 | 13431400413431 |
| 26 | 100000020000001 |
[0,1,4,121,10201,12321,114411,1002001,1234321, 100020001,102030201,121242121,131141131, 10000200001,10221412201,12102420121,131441144131, 1000002000001,1002003002001,1020304030201, 1143442443411,1210024200121,4133144413314, 4342230322434,13431400413431,100000020000001] |