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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 57 |
| 5 | 289 |
| 6 | 1739 |
| 7 | 12179 |
| 8 | 97436 |
| 9 | 876928 |
| 10 | 8769282 |
| 11 | 96462104 |
| 12 | 1157545250 |
| 13 | 15048088262 |
| 14 | 210673235669 |
| 15 | 3160098535044 |
| 16 | 50561576560713 |
| 17 | 859546801532132 |
| 18 | 15471842427578387 |
| 19 | 293965006123989362 |
| 20 | 5879300122479787241 |
[2,4,14,57,289,1739,12179,97436,876928,8769282, 96462104,1157545250,15048088262,210673235669, 3160098535044,50561576560713,859546801532132, 15471842427578387,293965006123989362, 5879300122479787241] |