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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 13 |
| 3 | 147 |
| 4 | 1625 |
| 5 | 17891 |
| 6 | 196833 |
| 7 | 2165227 |
| 8 | 23817625 |
| 9 | 261994131 |
| 10 | 2881935943 |
| 11 | 31701296375 |
| 12 | 348714262017 |
| 13 | 3835856884757 |
| 14 | 42194425724149 |
| 15 | 464138682802857 |
| 16 | 5105525508895321 |
| 17 | 56160780576260645 |
| 18 | 617768586100819485 |
| 19 | 6795454444489330049 |
| 20 | 74749998860563784655 |
[0,1,13,147,1625,17891,196833,2165227,23817625, 261994131,2881935943,31701296375,348714262017, 3835856884757,42194425724149,464138682802857, 5105525508895321,56160780576260645, 617768586100819485,6795454444489330049, 74749998860563784655] |