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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 20 |
| 4 | 401 |
| 5 | 35202 |
| 6 | 7942712 |
| 7 | 5423213789 |
| 8 | 10714890351493 |
| 9 | 61977591097741664 |
| 10 | 1045534716234234877628 |
| 11 | 51543884247862488090471612 |
[1,1,20,401,35202,7942712,5423213789, 10714890351493,61977591097741664, 1045534716234234877628,51543884247862488090471612] |