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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 75 |
| 6 | 267 |
| 7 | 985 |
| 8 | 3757 |
| 9 | 14741 |
| 10 | 59037 |
| 11 | 240969 |
| 12 | 998175 |
| 13 | 4189717 |
| 14 | 17780797 |
| 15 | 76195667 |
| 16 | 329283701 |
| 17 | 1433632569 |
| 18 | 6283001549 |
| 19 | 27697690653 |
| 20 | 122745242869 |
| 21 | 546537971273 |
| 22 | 2443964016413 |
| 23 | 10971244278385 |
| 24 | 49425837888159 |
| 25 | 223386723435727 |
| 26 | 1012627133118973 |
| 27 | 4602856954298743 |
| 28 | 20974868546005303 |
[1,1,3,7,23,75,267,985,3757,14741,59037,240969, 998175,4189717,17780797,76195667,329283701, 1433632569,6283001549,27697690653,122745242869, 546537971273,2443964016413,10971244278385, 49425837888159,223386723435727,1012627133118973, 4602856954298743,20974868546005303] |