The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 17 |
| 4 | 75 |
| 5 | 285 |
| 6 | 1309 |
| 7 | 5515 |
| 8 | 25679 |
| 9 | 112633 |
| 10 | 530845 |
| 11 | 2393671 |
| 12 | 11381751 |
| 13 | 52290385 |
| 14 | 250260427 |
| 15 | 1165119535 |
| 16 | 5604533791 |
| 17 | 26355813965 |
| 18 | 127289400889 |
| 19 | 603273589021 |
| 20 | 2923117726291 |
| 21 | 13939944270725 |
| 22 | 67727672763965 |
| 23 | 324616185194801 |
| 24 | 1580747352700737 |
| 25 | 7608095484588771 |
| 26 | 37120200203145903 |
| 27 | 179283568333680023 |
[1,1,5,17,75,285,1309,5515,25679,112633,530845, 2393671,11381751,52290385,250260427,1165119535, 5604533791,26355813965,127289400889,603273589021, 2923117726291,13939944270725,67727672763965, 324616185194801,1580747352700737,7608095484588771, 37120200203145903,179283568333680023] |