The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 38 |
| 4 | 228 |
| 5 | 1562 |
| 6 | 12386 |
| 7 | 109286 |
| 8 | 1073988 |
| 9 | 11545994 |
| 10 | 135393438 |
| 11 | 1714890806 |
| 12 | 23380747506 |
| 13 | 341014477390 |
| 14 | 5303722839850 |
| 15 | 87582446980418 |
| 16 | 1531259993710468 |
| 17 | 28254163132485930 |
| 18 | 548854481037814382 |
| 19 | 11196310379931318758 |
| 20 | 239346426732701009838 |
| 21 | 5350768890908294837294 |
[1,2,8,38,228,1562,12386,109286,1073988,11545994, 135393438,1714890806,23380747506,341014477390, 5303722839850,87582446980418,1531259993710468, 28254163132485930,548854481037814382, 11196310379931318758,239346426732701009838, 5350768890908294837294] |