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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | 127 |
| 6 | 1650 |
| 7 | 23258 |
| 8 | 361154 |
| 9 | 6131236 |
| 10 | 113042841 |
| 11 | 2248848796 |
| 12 | 47985568177 |
| 13 | 1092290052791 |
| 14 | 26397613960112 |
| 15 | 674479517926073 |
| 16 | 18153075875657428 |
| 17 | 512977569857121559 |
| 18 | 15176209471995304906 |
| 19 | 468847646698743759887 |
| 20 | 15090613008931715532300 |
[1,0,0,1,10,127,1650,23258,361154,6131236, 113042841,2248848796,47985568177,1092290052791, 26397613960112,674479517926073,18153075875657428, 512977569857121559,15176209471995304906, 468847646698743759887,15090613008931715532300] |