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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 12 |
| 3 | 150 |
| 4 | 1944 |
| 5 | 25992 |
| 6 | 356832 |
| 7 | 5008824 |
| 8 | 71629920 |
| 9 | 1040509152 |
| 10 | 15315578496 |
| 11 | 227981324736 |
| 12 | 3426473187072 |
| 13 | 51929043390720 |
| 14 | 792725911280640 |
| 15 | 12178706839758720 |
| 16 | 188158789025809920 |
| 17 | 2921622674591946240 |
[1,1,12,150,1944,25992,356832,5008824,71629920, 1040509152,15315578496,227981324736,3426473187072, 51929043390720,792725911280640,12178706839758720, 188158789025809920,2921622674591946240] |