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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -12 |
| 5 | 109 |
| 6 | -405 |
| 7 | 4913 |
| 8 | -24976 |
| 9 | 372633 |
| 10 | -2419425 |
| 11 | 42646845 |
| 12 | -338219244 |
| 13 | 6863821509 |
| 14 | -64452230661 |
| 15 | 1478191260393 |
| 16 | -16062969072000 |
| 17 | 410493211996977 |
| 18 | -5072547848554017 |
| 19 | 142840036992492789 |
| 20 | -1979718755185227180 |
[0,1,-1,5,-12,109,-405,4913,-24976,372633, -2419425,42646845,-338219244,6863821509, -64452230661,1478191260393,-16062969072000, 410493211996977,-5072547848554017, 142840036992492789,-1979718755185227180] |