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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 13 |
| 4 | 40 |
| 5 | 131 |
| 6 | 452 |
| 7 | 1562 |
| 8 | 5644 |
| 9 | 20799 |
| 10 | 78589 |
| 11 | 297261 |
| 12 | 1148443 |
| 13 | 4476655 |
| 14 | 17703933 |
| 15 | 70069434 |
| 16 | 280865518 |
| 17 | 1131469211 |
| 18 | 4601137351 |
| 19 | 18721075331 |
| 20 | 76825846434 |
| 21 | 316282614821 |
| 22 | 1310738384205 |
| 23 | 5434178009491 |
| 24 | 22669009843172 |
| 25 | 94776209742645 |
| 26 | 398203425052616 |
| 27 | 1673579306464051 |
| 28 | 7066742149099808 |
[1,2,5,13,40,131,452,1562,5644,20799,78589,297261, 1148443,4476655,17703933,70069434,280865518, 1131469211,4601137351,18721075331,76825846434, 316282614821,1310738384205,5434178009491, 22669009843172,94776209742645,398203425052616, 1673579306464051,7066742149099808] |