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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 20 |
| 4 | 0 |
| 5 | -1560 |
| 6 | -26825 |
| 7 | -272000 |
| 8 | 0 |
| 9 | 84086080 |
| 10 | 2484885325 |
| 11 | 40560998400 |
| 12 | 0 |
| 13 | -28152429760000 |
| 14 | -1180588763732625 |
| 15 | -26582971351040000 |
| 16 | 0 |
| 17 | 32774236110420480000 |
| 18 | 1780605230870046303125 |
| 19 | 51128938217766256640000 |
| 20 | 0 |
| 21 | -98456230888859903488000000 |
| 22 | -6569779608356896665959265625 |
[0,1,5,20,0,-1560,-26825,-272000,0,84086080, 2484885325,40560998400,0,-28152429760000, -1180588763732625,-26582971351040000,0, 32774236110420480000,1780605230870046303125, 51128938217766256640000,0, -98456230888859903488000000, -6569779608356896665959265625] |