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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 14 |
| 4 | 42 |
| 5 | 131 |
| 6 | 420 |
| 7 | 1376 |
| 8 | 4589 |
| 9 | 15537 |
| 10 | 53293 |
| 11 | 184881 |
| 12 | 647752 |
| 13 | 2289215 |
| 14 | 8152147 |
| 15 | 29226618 |
| 16 | 105408688 |
| 17 | 382193502 |
| 18 | 1392377762 |
| 19 | 5094356032 |
| 20 | 18711122069 |
| 21 | 68965586862 |
| 22 | 255006331944 |
| 23 | 945662753514 |
| 24 | 3516281928159 |
| 25 | 13106923073426 |
| 26 | 48967229534156 |
| 27 | 183326438562982 |
[1,2,5,14,42,131,420,1376,4589,15537,53293,184881, 647752,2289215,8152147,29226618,105408688, 382193502,1392377762,5094356032,18711122069, 68965586862,255006331944,945662753514, 3516281928159,13106923073426,48967229534156, 183326438562982] |