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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 164 |
| 5 | 4930 |
| 6 | 222468 |
| 7 | 13846245 |
| 8 | 1133788866 |
| 9 | 118120672980 |
| 10 | 15268514307713 |
| 11 | 2398373104558453 |
[1,0,1,9,164,4930,222468,13846245,1133788866, 118120672980,15268514307713,2398373104558453] |