The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 23 |
| 4 | 86 |
| 5 | 247 |
| 6 | 849 |
| 7 | 2578 |
| 8 | 8521 |
| 9 | 26567 |
| 10 | 86214 |
| 11 | 272183 |
| 12 | 875681 |
| 13 | 2780962 |
| 14 | 8910729 |
| 15 | 28377463 |
| 16 | 90752566 |
| 17 | 289394807 |
| 18 | 924662769 |
| 19 | 2950426418 |
| 20 | 9423065801 |
| 21 | 30076050727 |
| 22 | 96037511334 |
| 23 | 306569866423 |
| 24 | 978832445761 |
| 25 | 3124821510722 |
[1,2,9,23,86,247,849,2578,8521,26567,86214,272183, 875681,2780962,8910729,28377463,90752566, 289394807,924662769,2950426418,9423065801, 30076050727,96037511334,306569866423,978832445761, 3124821510722] |