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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 3 |
| 5 | 15 |
| 6 | 45 |
| 7 | 315 |
| 8 | 45 |
| 9 | 2835 |
| 10 | 14175 |
| 11 | 155925 |
| 12 | 66825 |
| 13 | 6081075 |
| 14 | 42567525 |
| 15 | 91216125 |
| 16 | 638512875 |
| 17 | 10854718875 |
| 18 | 97692469875 |
| 19 | 2228279625 |
| 20 | 9280784638125 |
| 21 | 14992036723125 |
| 22 | 18015640768125 |
| 23 | 49308808782358125 |
| 24 | 147926426347074375 |
[1,1,1,3,3,15,45,315,45,2835,14175,155925,66825, 6081075,42567525,91216125,638512875,10854718875, 97692469875,2228279625,9280784638125, 14992036723125,18015640768125,49308808782358125, 147926426347074375] |