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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 10 |
| 7 | 52 |
| 8 | 459 |
| 9 | 1271 |
| 10 | 10094 |
| 11 | 63133 |
| 12 | 547565 |
| 13 | 4431517 |
| 14 | 42046100 |
| 15 | 400782747 |
| 16 | 8711476734 |
[0,0,1,1,3,10,52,459,1271,10094,63133,547565, 4431517,42046100,400782747,8711476734] |