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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 69 |
| 5 | 271 |
| 6 | 1143 |
| 7 | 4861 |
| 8 | 21075 |
| 9 | 92001 |
| 10 | 405747 |
| 11 | 1803693 |
| 12 | 8071737 |
| 13 | 36317843 |
| 14 | 164127723 |
| 15 | 744693295 |
| 16 | 3390805227 |
| 17 | 15488141433 |
| 18 | 70940866119 |
| 19 | 325734483267 |
| 20 | 1498990629875 |
| 21 | 6912126391031 |
| 22 | 31932076989425 |
| 23 | 147766233863115 |
| 24 | 684852872148647 |
| 25 | 3178630119704709 |
| 26 | 14772626581189619 |
| 27 | 68739890873719931 |
[1,1,5,17,69,271,1143,4861,21075,92001,405747, 1803693,8071737,36317843,164127723,744693295, 3390805227,15488141433,70940866119,325734483267, 1498990629875,6912126391031,31932076989425, 147766233863115,684852872148647,3178630119704709, 14772626581189619,68739890873719931] |