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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 7 |
| 4 | 13 |
| 5 | 26 |
| 6 | 58 |
| 7 | 147 |
| 8 | 423 |
| 9 | 1366 |
| 10 | 4880 |
| 11 | 19039 |
| 12 | 80281 |
| 13 | 362914 |
| 14 | 1747598 |
| 15 | 8918299 |
| 16 | 48024291 |
| 17 | 271891710 |
| 18 | 1613325844 |
| 19 | 10005690695 |
| 20 | 64702147429 |
| 21 | 435311589418 |
| 22 | 3041246276098 |
| 23 | 22024930755299 |
| 24 | 165082467634303 |
| 25 | 1278742554953574 |
[1,2,4,7,13,26,58,147,423,1366,4880,19039,80281, 362914,1747598,8918299,48024291,271891710, 1613325844,10005690695,64702147429,435311589418, 3041246276098,22024930755299,165082467634303, 1278742554953574] |