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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | -6 |
| 4 | -12 |
| 5 | 140 |
| 6 | 1020 |
| 7 | -5208 |
| 8 | -117264 |
| 9 | -2448 |
| 10 | 17756640 |
| 11 | 117905040 |
| 12 | -3177424800 |
| 13 | -56997933408 |
| 14 | 523176632160 |
| 15 | 25824592321920 |
| 16 | 31907065317120 |
| 17 | -12118922683971840 |
| 18 | -151839867298498560 |
| 19 | 5619086944920958464 |
| 20 | 172859973799199892480 |
| 21 | -1989399401447725854720 |
| 22 | -170925579909303883614720 |
[1,1,0,-6,-12,140,1020,-5208,-117264,-2448, 17756640,117905040,-3177424800,-56997933408, 523176632160,25824592321920,31907065317120, -12118922683971840,-151839867298498560, 5619086944920958464,172859973799199892480, -1989399401447725854720,-170925579909303883614720] |