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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 26 |
| 4 | 334 |
| 5 | 5964 |
| 6 | 135228 |
| 7 | 3729872 |
| 8 | 121172560 |
| 9 | 4532603904 |
| 10 | 191869653120 |
| 11 | 9067948437888 |
| 12 | 473297792213376 |
| 13 | 27039987154142208 |
| 14 | 1678363256057198592 |
| 15 | 112467293224249912320 |
| 16 | 8092242817059530284032 |
| 17 | 622253112192770288799744 |
[0,1,3,26,334,5964,135228,3729872,121172560, 4532603904,191869653120,9067948437888, 473297792213376,27039987154142208, 1678363256057198592,112467293224249912320, 8092242817059530284032,622253112192770288799744] |