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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 7 |
| 6 | 21 |
| 7 | 61 |
| 8 | 187 |
| 9 | 583 |
| 10 | 1837 |
| 11 | 5885 |
| 12 | 19027 |
| 13 | 62167 |
| 14 | 204917 |
| 15 | 680621 |
| 16 | 2275211 |
| 17 | 7648519 |
| 18 | 25852573 |
| 19 | 87812093 |
| 20 | 299349795 |
| 21 | 1023570647 |
| 22 | 3515918501 |
| 23 | 12140103149 |
| 24 | 41894710427 |
| 25 | 143835281351 |
| 26 | 501071173901 |
| 27 | 1808088546557 |
| 28 | 6212411239539 |
| 29 | 17720665594455 |
[1,1,1,3,7,21,61,187,583,1837,5885,19027,62167, 204917,680621,2275211,7648519,25852573,87812093, 299349795,1023570647,3515918501,12140103149, 41894710427,143835281351,501071173901, 1808088546557,6212411239539,17720665594455] |