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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 39 |
| 3 | 169 |
| 4 | 715 |
| 5 | 3025 |
| 6 | 12815 |
| 7 | 54289 |
| 8 | 229971 |
| 9 | 974169 |
| 10 | 4126647 |
| 11 | 17480761 |
| 12 | 74049691 |
| 13 | 313679521 |
| 14 | 1328767775 |
| 15 | 5628750625 |
| 16 | 23843770275 |
| 17 | 101003831721 |
| 18 | 427859097159 |
| 19 | 1812440220361 |
| 20 | 7677619978603 |
| 21 | 32522920134769 |
| 22 | 137769300517679 |
[9,39,169,715,3025,12815,54289,229971,974169, 4126647,17480761,74049691,313679521,1328767775, 5628750625,23843770275,101003831721,427859097159, 1812440220361,7677619978603,32522920134769, 137769300517679] |