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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 55 |
| 5 | -162 |
| 6 | 4100 |
| 7 | -49030 |
| 8 | 779914 |
| 9 | -11928008 |
| 10 | 198650880 |
| 11 | -3538477560 |
| 12 | 70414760136 |
| 13 | -1571134087824 |
| 14 | 38788172175072 |
| 15 | -1028732373217200 |
| 16 | 28631225505910224 |
| 17 | -826097667884640768 |
| 18 | 24664145505337921920 |
| 19 | -765245501125015575168 |
| 20 | 24841409653689047496576 |
[1,4,7,55,-162,4100,-49030,779914,-11928008, 198650880,-3538477560,70414760136,-1571134087824, 38788172175072,-1028732373217200, 28631225505910224,-826097667884640768, 24664145505337921920,-765245501125015575168, 24841409653689047496576] |