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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 45 |
| 2 | 1980 |
| 3 | 87120 |
| 4 | 3833280 |
| 5 | 168664320 |
| 6 | 7421230080 |
| 7 | 326534122530 |
| 8 | 14367501347760 |
| 9 | 632170057385790 |
| 10 | 27815482440686160 |
| 11 | 1223881223681492640 |
| 12 | 53850773678802946560 |
| 13 | 2369434034687289546240 |
| 14 | 104255097210318976508070 |
[1,45,1980,87120,3833280,168664320,7421230080, 326534122530,14367501347760,632170057385790, 27815482440686160,1223881223681492640, 53850773678802946560,2369434034687289546240, 104255097210318976508070] |