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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 120 |
| 2 | 291720 |
| 3 | 1085674320 |
| 4 | 4927561419120 |
| 5 | 25071989721176760 |
| 6 | 137401053406474591320 |
| 7 | 793279085081986319145120 |
| 8 | 4760210822189950253433759120 |
| 9 | 29426738284267047709626231969120 |
| 10 | 186257720453050086737999575854359760 |
| 11 | 1201788369927033696254110199515917069120 |
[1,120,291720,1085674320,4927561419120, 25071989721176760,137401053406474591320, 793279085081986319145120, 4760210822189950253433759120, 29426738284267047709626231969120, 186257720453050086737999575854359760, 1201788369927033696254110199515917069120] |