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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 9 |
| 4 | 80 |
| 5 | 875 |
| 6 | 11880 |
| 7 | 192080 |
| 8 | 3608576 |
| 9 | 77295141 |
| 10 | 1860100000 |
| 11 | 49701143855 |
| 12 | 1460328321024 |
| 13 | 46805373800640 |
| 14 | 1625353003293824 |
| 15 | 60796114850390625 |
| 16 | 2437185999638364160 |
| 17 | 104248664384022862523 |
| 18 | 4739500894223556407808 |
[0,2,9,80,875,11880,192080,3608576,77295141, 1860100000,49701143855,1460328321024, 46805373800640,1625353003293824,60796114850390625, 2437185999638364160,104248664384022862523, 4739500894223556407808] |