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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 66 |
| 3 | 21222 |
| 4 | 18927560 |
| 5 | 36030104000 |
| 6 | 125486684755152 |
| 7 | 722272396672485568 |
| 8 | 6391048590559497227904 |
| 9 | 82362961035803105954736768 |
| 10 | 1482370265813455598541301007360 |
| 11 | 36031982428595760278113744699088384 |
| 12 | 1150873035676373345725887922070318410752 |
[1,1,66,21222,18927560,36030104000, 125486684755152,722272396672485568, 6391048590559497227904,82362961035803105954736768, 1482370265813455598541301007360, 36031982428595760278113744699088384, 1150873035676373345725887922070318410752] |