The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 32 |
| 4 | 138 |
| 5 | 604 |
| 6 | 2703 |
| 7 | 12315 |
| 8 | 56663 |
| 9 | 263196 |
| 10 | 1230758 |
| 11 | 5788966 |
| 12 | 27366503 |
| 13 | 129887780 |
| 14 | 618733335 |
| 15 | 2956325427 |
| 16 | 14163969859 |
| 17 | 68023437777 |
| 18 | 327380888885 |
| 19 | 1578644180769 |
| 20 | 7625361651529 |
| 21 | 36890862105021 |
| 22 | 178729294951629 |
| 23 | 867041001587589 |
| 24 | 4211192195399009 |
| 25 | 20476247078858780 |
| 26 | 99664557968320422 |
[1,2,8,32,138,604,2703,12315,56663,263196,1230758, 5788966,27366503,129887780,618733335,2956325427, 14163969859,68023437777,327380888885, 1578644180769,7625361651529,36890862105021, 178729294951629,867041001587589,4211192195399009, 20476247078858780,99664557968320422] |