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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 19 |
| 3 | 115 |
| 4 | 739 |
| 5 | 4679 |
| 6 | 29569 |
| 7 | 187211 |
| 8 | 1185283 |
| 9 | 7502685 |
| 10 | 47491531 |
| 11 | 300627179 |
| 12 | 1902998895 |
| 13 | 12046125511 |
| 14 | 76252939087 |
| 15 | 482687382245 |
| 16 | 3055450450511 |
| 17 | 19341249601691 |
| 18 | 122431683941789 |
| 19 | 775002524638781 |
| 20 | 4905829047952315 |
[3,19,115,739,4679,29569,187211,1185283,7502685, 47491531,300627179,1902998895,12046125511, 76252939087,482687382245,3055450450511, 19341249601691,122431683941789,775002524638781, 4905829047952315] |