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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 51 |
| 4 | 442 |
| 5 | 4534 |
| 6 | 51182 |
| 7 | 613806 |
| 8 | 7675397 |
| 9 | 98971497 |
| 10 | 1306630823 |
| 11 | 17575262387 |
| 12 | 240012293969 |
| 13 | 3319086310532 |
| 14 | 46386983964844 |
| 15 | 654176372802786 |
| 16 | 9297814382343636 |
| 17 | 133052398800475776 |
| 18 | 1915431497096942109 |
| 19 | 27721644693710659258 |
[1,2,8,51,442,4534,51182,613806,7675397,98971497, 1306630823,17575262387,240012293969,3319086310532, 46386983964844,654176372802786,9297814382343636, 133052398800475776,1915431497096942109, 27721644693710659258] |