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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 12 |
| 4 | 504 |
| 5 | 54552 |
| 6 | 18314238 |
| 7 | 18001425828 |
| 8 | 52877461613730 |
| 9 | 461270181887973636 |
| 10 | 11975672062199372507844 |
| 11 | 924700036496758370728369296 |
[0,1,12,504,54552,18314238,18001425828, 52877461613730,461270181887973636, 11975672062199372507844, 924700036496758370728369296] |