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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 171 |
| 4 | 1512 |
| 5 | 14040 |
| 6 | 134775 |
| 7 | 1325457 |
| 8 | 13279329 |
| 9 | 135014931 |
| 10 | 1389328200 |
| 11 | 14440275000 |
| 12 | 151366896639 |
| 13 | 1598281697205 |
| 14 | 16983592285797 |
| 15 | 181478066048739 |
| 16 | 1948770301135167 |
| 17 | 21018820972926429 |
| 18 | 227600123488744275 |
| 19 | 2473358642698093245 |
| 20 | 26965560597470251857 |
[1,3,21,171,1512,14040,134775,1325457,13279329, 135014931,1389328200,14440275000,151366896639, 1598281697205,16983592285797,181478066048739, 1948770301135167,21018820972926429, 227600123488744275,2473358642698093245, 26965560597470251857] |