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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 20160 |
| 4 | 1067544 |
| 5 | 37051840 |
| 6 | 801494400 |
| 7 | 11684617344 |
| 8 | 119266575708 |
| 9 | 879321948288 |
| 10 | 4789977429888 |
| 11 | 19616032446528 |
| 12 | 61193769988008 |
| 13 | 146864398476096 |
| 14 | 273137809339136 |
| 15 | 395577405119232 |
| 16 | 447418802536902 |
| 17 | 395577405119232 |
| 18 | 273137809339136 |
| 19 | 146864398476096 |
[1,0,0,20160,1067544,37051840,801494400, 11684617344,119266575708,879321948288, 4789977429888,19616032446528,61193769988008, 146864398476096,273137809339136,395577405119232, 447418802536902,395577405119232,273137809339136, 146864398476096] |