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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 23 |
| 2 | 181 |
| 3 | 1457 |
| 4 | 11953 |
| 5 | 99593 |
| 6 | 840241 |
| 7 | 7160057 |
| 8 | 61503553 |
| 9 | 531715913 |
| 10 | 4620992401 |
| 11 | 40333791257 |
| 12 | 353325795553 |
| 13 | 3104682336233 |
| 14 | 27353203130161 |
| 15 | 241545689168057 |
| 16 | 2137316275469953 |
| 17 | 18945908172796553 |
| 18 | 168210593763149521 |
[3,23,181,1457,11953,99593,840241,7160057, 61503553,531715913,4620992401,40333791257, 353325795553,3104682336233,27353203130161, 241545689168057,2137316275469953, 18945908172796553,168210593763149521] |