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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 416 |
| 3 | 664958 |
| 4 | 1792874048 |
| 5 | 6232521421502 |
| 6 | 25328979140590460 |
| 7 | 114573118435555703030 |
| 8 | 560523113474283819256640 |
| 9 | 2911820015993491302722966990 |
| 10 | 15861703283168731825003935183416 |
| 11 | 89796737967084981726163781067177194 |
| 12 | 524830705066715697873367329722967841532 |
[1,2,416,664958,1792874048,6232521421502, 25328979140590460,114573118435555703030, 560523113474283819256640, 2911820015993491302722966990, 15861703283168731825003935183416, 89796737967084981726163781067177194, 524830705066715697873367329722967841532] |