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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 7 |
| 2 | 69 |
| 3 | 571 |
| 4 | 4729 |
| 5 | 39227 |
| 6 | 325305 |
| 7 | 2697779 |
| 8 | 22372865 |
| 9 | 185539675 |
| 10 | 1538693049 |
| 11 | 12760485283 |
| 12 | 105823565521 |
| 13 | 877601969771 |
| 14 | 7278012355305 |
| 15 | 60357047577971 |
| 16 | 500545068417473 |
| 17 | 4151054028833851 |
| 18 | 34424971171479513 |
| 19 | 285488608899199939 |
| 20 | 2367576298182197809 |
| 21 | 19634470003296261131 |
[3,7,69,571,4729,39227,325305,2697779,22372865, 185539675,1538693049,12760485283,105823565521, 877601969771,7278012355305,60357047577971, 500545068417473,4151054028833851, 34424971171479513,285488608899199939, 2367576298182197809,19634470003296261131] |