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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 297 |
| 4 | 2368 |
| 5 | 9484 |
| 6 | 29408 |
| 7 | 85874 |
| 8 | 239368 |
| 9 | 635490 |
| 10 | 1614888 |
| 11 | 3982412 |
| 12 | 9598424 |
| 13 | 22720722 |
[0,0,297,2368,9484,29408,85874,239368,635490, 1614888,3982412,9598424,22720722] |