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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 117 |
| 3 | 1962 |
| 4 | 40122 |
| 5 | 966276 |
| 6 | 26755812 |
| 7 | 836862192 |
| 8 | 29167596504 |
| 9 | 1120629465432 |
| 10 | 47044646845848 |
| 11 | 2142210019297680 |
| 12 | 105154320625284240 |
| 13 | 5534780654854980000 |
| 14 | 310945503593770489440 |
| 15 | 18570787974013838515200 |
| 16 | 1174884522886771261079040 |
[1,9,117,1962,40122,966276,26755812,836862192, 29167596504,1120629465432,47044646845848, 2142210019297680,105154320625284240, 5534780654854980000,310945503593770489440, 18570787974013838515200,1174884522886771261079040] |