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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 28 |
| 6 | 924 |
| 7 | 1301916 |
| 8 | 2192719475100 |
| 9 | 6877436791939871875340700 |
| 10 | 63662093585928604457207470763864412072759112460700 |
| 11 | 5654964592175973912056572385731364781410655247698710272187424640218106099883341821471858427090700700 |
[1,1,1,2,4,28,924,1301916,2192719475100, 6877436791939871875340700, 63662093585928604457207470763864412072759112460700\ , 56549645921759739120565723857313647814106552476987\ 10272187424640218106099883341821471858427090700700\ ] |