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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 8 |
| 5 | 240 |
| 6 | 2379 |
| 7 | 13860 |
| 8 | 379696 |
| 9 | 4839048 |
| 10 | 63662440 |
| 11 | 1689057480 |
| 12 | 27130512294 |
| 13 | 542163301680 |
| 14 | 14594796519968 |
| 15 | 290672365591620 |
| 16 | 7336896240946048 |
| 17 | 206683456014205872 |
| 18 | 4951125201195562248 |
| 19 | 144532076753308070352 |
| 20 | 4337041161081941767680 |
| 21 | 120922365106904865110208 |
[1,2,9,8,240,2379,13860,379696,4839048,63662440, 1689057480,27130512294,542163301680, 14594796519968,290672365591620,7336896240946048, 206683456014205872,4951125201195562248, 144532076753308070352,4337041161081941767680, 120922365106904865110208] |