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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 18 |
| 5 | 59 |
| 6 | 240 |
| 7 | 868 |
| 8 | 3712 |
| 9 | 14542 |
| 10 | 64196 |
| 11 | 264949 |
| 12 | 1197681 |
| 13 | 5121331 |
| 14 | 23540836 |
| 15 | 103253933 |
| 16 | 480622773 |
| 17 | 2149426077 |
| 18 | 10102076321 |
| 19 | 45872426353 |
| 20 | 217233749441 |
| 21 | 998548779839 |
| 22 | 4757602658234 |
| 23 | 22087478068902 |
| 24 | 105762797270235 |
| 25 | 495057532485748 |
| 26 | 2380396768175890 |
| 27 | 11218999479823552 |
| 28 | 54134391460404502 |
[1,1,2,5,18,59,240,868,3712,14542,64196,264949, 1197681,5121331,23540836,103253933,480622773, 2149426077,10102076321,45872426353,217233749441, 998548779839,4757602658234,22087478068902, 105762797270235,495057532485748,2380396768175890, 11218999479823552,54134391460404502] |