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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 45 |
| 4 | 45 |
| 5 | 15855 |
| 6 | 280665 |
| 7 | 4774980 |
| 8 | 4393585185 |
| 9 | 6522452145 |
| 10 | 166260770280 |
| 11 | 4321816939440 |
| 12 | 15939674132892510 |
| 13 | 22654052989616460555 |
| 14 | 22654052989616460555 |
| 15 | 202608454566431632290 |
[1,1,3,45,45,15855,280665,4774980,4393585185, 6522452145,166260770280,4321816939440, 15939674132892510,22654052989616460555, 22654052989616460555,202608454566431632290] |