The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 36 |
| 4 | 204 |
| 5 | 1222 |
| 6 | 7513 |
| 7 | 46950 |
| 8 | 296691 |
| 9 | 1890232 |
| 10 | 12118424 |
| 11 | 78080402 |
| 12 | 505134625 |
| 13 | 3279051382 |
| 14 | 21347213562 |
| 15 | 139319046744 |
| 16 | 911204289149 |
| 17 | 5970941722698 |
| 18 | 39192011365250 |
| 19 | 257632856738690 |
| 20 | 1695850232984011 |
[1,2,7,36,204,1222,7513,46950,296691,1890232, 12118424,78080402,505134625,3279051382, 21347213562,139319046744,911204289149, 5970941722698,39192011365250,257632856738690, 1695850232984011] |