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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 0 |
| 4 | 76 |
| 5 | 0 |
| 6 | 9816 |
| 7 | 0 |
| 8 | 2731408 |
| 9 | 0 |
| 10 | 1327394080 |
| 11 | 0 |
| 12 | 998915378880 |
| 13 | 0 |
| 14 | 1076892609950080 |
| 15 | 0 |
| 16 | 1575062807865569536 |
| 17 | 0 |
| 18 | 3002359129582191616512 |
| 19 | 0 |
| 20 | 7232182908954405203184640 |
| 21 | 0 |
| 22 | 21483641086491531479896545280 |
| 23 | 0 |
| 24 | 77155816749532379835853517131776 |
| 25 | 0 |
[1,0,2,0,76,0,9816,0,2731408,0,1327394080,0, 998915378880,0,1076892609950080,0, 1575062807865569536,0,3002359129582191616512,0, 7232182908954405203184640,0, 21483641086491531479896545280,0, 77155816749532379835853517131776,0] |