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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 568 |
| 4 | 39695 |
| 5 | 4431876 |
| 6 | 724082352 |
| 7 | 163050236504 |
| 8 | 48442719007503 |
| 9 | 18368207542264060 |
| 10 | 8659014569831436140 |
| 11 | 4968837728849467193040 |
| 12 | 3410836618457710864892912 |
| 13 | 2760233360074280192888992948 |
[1,15,568,39695,4431876,724082352,163050236504, 48442719007503,18368207542264060, 8659014569831436140,4968837728849467193040, 3410836618457710864892912, 2760233360074280192888992948] |