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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 6 |
| 6 | 25 |
| 7 | 84 |
| 8 | 397 |
| 9 | 1855 |
| 10 | 9708 |
| 11 | 51684 |
| 12 | 286011 |
| 13 | 1609097 |
| 14 | 9222409 |
| 15 | 53543338 |
| 16 | 314612803 |
[1,1,3,6,25,84,397,1855,9708,51684,286011,1609097, 9222409,53543338,314612803] |