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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 38 |
| 4 | 229 |
| 5 | 1374 |
| 6 | 8246 |
| 7 | 49477 |
| 8 | 296862 |
| 9 | 1781174 |
| 10 | 10687045 |
| 11 | 64122270 |
| 12 | 384733622 |
| 13 | 2308401733 |
| 14 | 13850410398 |
| 15 | 83102462390 |
| 16 | 498614774341 |
| 17 | 2991688646046 |
| 18 | 17950131876278 |
| 19 | 107700791257669 |
| 20 | 646204747546014 |
| 21 | 3877228485276086 |
[1,6,38,229,1374,8246,49477,296862,1781174, 10687045,64122270,384733622,2308401733, 13850410398,83102462390,498614774341, 2991688646046,17950131876278,107700791257669, 646204747546014,3877228485276086] |