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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 15 |
| 4 | 61 |
| 5 | 231 |
| 6 | 963 |
| 7 | 3883 |
| 8 | 16603 |
| 9 | 69357 |
| 10 | 301579 |
| 11 | 1289895 |
| 12 | 5675515 |
| 13 | 24684299 |
| 14 | 109567115 |
| 15 | 482388707 |
| 16 | 2156180879 |
| 17 | 9580954187 |
| 18 | 43072169001 |
| 19 | 192787715153 |
| 20 | 870874751157 |
| 21 | 3921099892891 |
| 22 | 17784852325551 |
| 23 | 80469582888555 |
| 24 | 366262434878891 |
| 25 | 1664043214385507 |
| 26 | 7597131200868419 |
| 27 | 34637812490666299 |
[1,1,5,15,61,231,963,3883,16603,69357,301579, 1289895,5675515,24684299,109567115,482388707, 2156180879,9580954187,43072169001,192787715153, 870874751157,3921099892891,17784852325551, 80469582888555,366262434878891,1664043214385507, 7597131200868419,34637812490666299] |