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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 66 |
| 3 | 936 |
| 4 | 14346 |
| 5 | 231876 |
| 6 | 3885456 |
| 7 | 66767616 |
| 8 | 1169068986 |
| 9 | 20769386796 |
| 10 | 373277526876 |
| 11 | 6772297456656 |
| 12 | 123834925330416 |
| 13 | 2279408745325536 |
| 14 | 42194656181618496 |
| 15 | 784905308800229376 |
| 16 | 14663340953943086106 |
| 17 | 274968958499402854716 |
| 18 | 5173516852494573136836 |
[1,6,66,936,14346,231876,3885456,66767616, 1169068986,20769386796,373277526876,6772297456656, 123834925330416,2279408745325536, 42194656181618496,784905308800229376, 14663340953943086106,274968958499402854716, 5173516852494573136836] |