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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 220 |
| 5 | 37283 |
| 6 | 19604624 |
| 7 | 40708113490 |
| 8 | 303433045764806 |
| 9 | 8209941324439372141 |
[0,1,9,220,37283,19604624,40708113490, 303433045764806,8209941324439372141] |