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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 10 |
| 4 | 120 |
| 5 | 1778 |
| 6 | 31685 |
| 7 | 661940 |
| 8 | 15882128 |
| 9 | 430607370 |
| 10 | 13022755068 |
| 11 | 434697574538 |
| 12 | 15875944361864 |
| 13 | 629756003982336 |
| 14 | 26963278837704185 |
| 15 | 1239382820431888898 |
| 16 | 60875147436141987437 |
| 17 | 3181961834442383306068 |
[1,0,1,10,120,1778,31685,661940,15882128, 430607370,13022755068,434697574538,15875944361864, 629756003982336,26963278837704185, 1239382820431888898,60875147436141987437, 3181961834442383306068] |