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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 108 |
| 4 | 1840 |
| 5 | 43000 |
| 6 | 1279584 |
| 7 | 46291280 |
| 8 | 1972707328 |
| 9 | 96793120800 |
| 10 | 5374542400000 |
| 11 | 333181247151808 |
| 12 | 22810832109895680 |
| 13 | 1709414039122395008 |
| 14 | 139174640542003978240 |
| 15 | 12233003976328500000000 |
| 16 | 1154537363767101233299456 |
| 17 | 116449585838640863629672960 |
| 18 | 12500573099908938063034318848 |
[1,2,10,108,1840,43000,1279584,46291280, 1972707328,96793120800,5374542400000, 333181247151808,22810832109895680, 1709414039122395008,139174640542003978240, 12233003976328500000000,1154537363767101233299456, 116449585838640863629672960, 12500573099908938063034318848] |