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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 70 |
| 9 | 1260 |
| 10 | 17850 |
| 11 | 242550 |
| 12 | 3350655 |
| 13 | 48108060 |
| 14 | 724403680 |
| 15 | 11478967500 |
| 16 | 191601229820 |
| 17 | 3367499575440 |
| 18 | 62253354650760 |
| 19 | 1208755315895400 |
| 20 | 24611454394536780 |
| 21 | 524613603866302440 |
| 22 | 11687734234226039220 |
| 23 | 271715852337632107020 |
[1,0,0,0,0,0,0,0,70,1260,17850,242550,3350655, 48108060,724403680,11478967500,191601229820, 3367499575440,62253354650760,1208755315895400, 24611454394536780,524613603866302440, 11687734234226039220,271715852337632107020] |