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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 16 |
| 5 | -50 |
| 6 | 488 |
| 7 | -3024 |
| 8 | 35376 |
| 9 | -313704 |
| 10 | 4361472 |
| 11 | -52901640 |
| 12 | 869275680 |
| 13 | -13360922640 |
| 14 | 252154734960 |
| 15 | -4681650438360 |
| 16 | 100596004131840 |
| 17 | -2186713427586240 |
| 18 | 52870374675586560 |
| 19 | -1312523172135192960 |
[0,0,2,-3,16,-50,488,-3024,35376,-313704,4361472, -52901640,869275680,-13360922640,252154734960, -4681650438360,100596004131840,-2186713427586240, 52870374675586560,-1312523172135192960] |