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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 11 |
| 5 | 80 |
| 6 | 7572 |
| 7 | 664475 |
| 8 | 3180929 |
| 9 | 120796790 |
| 10 | 556068798 |
| 11 | 1246707529 |
| 12 | 87037147316 |
[0,1,2,11,80,7572,664475,3180929,120796790, 556068798,1246707529,87037147316] |