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| n | a(n) |
|---|---|
| 7 | 1 |
| 8 | 28 |
| 9 | 714 |
| 10 | 17220 |
| 11 | 424809 |
| 12 | 11002068 |
| 13 | 303874714 |
| 14 | 9016296289 |
| 15 | 288135739892 |
| 16 | 9913826194272 |
| 17 | 366486926833846 |
| 18 | 14513217676764534 |
| 19 | 613646633464214863 |
| 20 | 27609928896732666760 |
| 21 | 1317652578222779606269 |
| 22 | 66497975770225498765728 |
| 23 | 3538905411811229060814213 |
[1,28,714,17220,424809,11002068,303874714, 9016296289,288135739892,9913826194272, 366486926833846,14513217676764534, 613646633464214863,27609928896732666760, 1317652578222779606269,66497975770225498765728, 3538905411811229060814213] |