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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 51 |
| 6 | 175 |
| 7 | 603 |
| 8 | 2179 |
| 9 | 7966 |
| 10 | 30115 |
| 11 | 115175 |
| 12 | 447599 |
| 13 | 1754566 |
| 14 | 6960211 |
| 15 | 27838776 |
| 16 | 112401002 |
| 17 | 457156790 |
| 18 | 1872092533 |
| 19 | 7709515518 |
| 20 | 31925277406 |
| 21 | 132858964434 |
| 22 | 555535209096 |
| 23 | 2332992606313 |
| 24 | 9836786434533 |
| 25 | 41626228814418 |
| 26 | 176751460040269 |
| 27 | 752917025247036 |
| 28 | 3216949479854651 |
[1,1,2,5,16,51,175,603,2179,7966,30115,115175, 447599,1754566,6960211,27838776,112401002, 457156790,1872092533,7709515518,31925277406, 132858964434,555535209096,2332992606313, 9836786434533,41626228814418,176751460040269, 752917025247036,3216949479854651] |