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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -2 |
| 3 | 7 |
| 4 | -28 |
| 5 | 185 |
| 6 | -1352 |
| 7 | 12367 |
| 8 | -129568 |
| 9 | 1558865 |
| 10 | -21053312 |
| 11 | 316097527 |
| 12 | -5218724608 |
| 13 | 94003171145 |
| 14 | -1834214761472 |
| 15 | 38543705698687 |
| 16 | -867787269787648 |
| 17 | 20840298552277025 |
| 18 | -531768169691512832 |
| 19 | 14366953364916735847 |
| 20 | -409720712943913074688 |
[0,1,-2,7,-28,185,-1352,12367,-129568,1558865, -21053312,316097527,-5218724608,94003171145, -1834214761472,38543705698687,-867787269787648, 20840298552277025,-531768169691512832, 14366953364916735847,-409720712943913074688] |