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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 660 |
| 3 | 48720 |
| 4 | 4005540 |
| 5 | 349260912 |
| 6 | 31626298704 |
| 7 | 2940502593600 |
| 8 | 278788387440420 |
| 9 | 26831860080682800 |
| 10 | 2613367831568654160 |
| 11 | 257012469788428710720 |
| 12 | 25479526081439438845200 |
| 13 | 2543092744417831625342400 |
| 14 | 255292245777771431285140800 |
| 15 | 25755871314484468746363582720 |
[1,12,660,48720,4005540,349260912,31626298704, 2940502593600,278788387440420,26831860080682800, 2613367831568654160,257012469788428710720, 25479526081439438845200,2543092744417831625342400, 255292245777771431285140800, 25755871314484468746363582720] |