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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 17 |
| 3 | 111 |
| 4 | 769 |
| 5 | 5503 |
| 6 | 40193 |
| 7 | 297727 |
| 8 | 2228225 |
| 9 | 16807935 |
| 10 | 127574017 |
| 11 | 973168639 |
| 12 | 7454392321 |
| 13 | 57298911231 |
| 14 | 441739706369 |
| 15 | 3414246490111 |
| 16 | 26447737520129 |
| 17 | 205272288591871 |
| 18 | 1595964714385409 |
| 19 | 12427568655368191 |
| 20 | 96905907580960769 |
| 21 | 756583504975757311 |
| 22 | 5913649000782757889 |
[1,3,17,111,769,5503,40193,297727,2228225, 16807935,127574017,973168639,7454392321, 57298911231,441739706369,3414246490111, 26447737520129,205272288591871,1595964714385409, 12427568655368191,96905907580960769, 756583504975757311,5913649000782757889] |