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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 3 |
| 8 | 7 |
| 9 | 13 |
| 10 | 26 |
| 11 | 70 |
| 12 | 233 |
| 13 | 869 |
| 14 | 3436 |
| 15 | 14680 |
| 16 | 71757 |
| 17 | 413520 |
| 18 | 2721699 |
| 19 | 19996282 |
| 20 | 163378650 |
| 21 | 1508376980 |
| 22 | 15870814986 |
| 23 | 189905190363 |
| 24 | 2566140210269 |
| 25 | 39033535389467 |
| 26 | 670295254576489 |
| 27 | 13033170011033515 |
| 28 | 287051699463343610 |
[1,1,1,1,1,1,3,7,13,26,70,233,869,3436,14680, 71757,413520,2721699,19996282,163378650, 1508376980,15870814986,189905190363,2566140210269, 39033535389467,670295254576489,13033170011033515, 287051699463343610] |