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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 65 |
| 4 | 3297 |
| 5 | 2537672 |
| 6 | 412184904221 |
| 7 | 4132070624893905681577 |
| 8 | 174224571863520492218909428465944685216436 |
| 9 | 133392486801388257127953774730008469745829658368044283629394202488602260177922751 |
[0,1,6,65,3297,2537672,412184904221, 4132070624893905681577, 174224571863520492218909428465944685216436, 13339248680138825712795377473000846974582965836804\ 4283629394202488602260177922751] |