The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 8 |
| 4 | 48 |
| 5 | 261 |
| 6 | 1358 |
| 7 | 6907 |
| 8 | 34683 |
| 9 | 172827 |
| 10 | 857077 |
| 11 | 4237179 |
| 12 | 20904293 |
| 13 | 102987450 |
| 14 | 506887889 |
| 15 | 2493127016 |
| 16 | 12256531946 |
| 17 | 60233878032 |
| 18 | 295941325816 |
| 19 | 1453755559520 |
| 20 | 7140344796458 |
| 21 | 35067449154442 |
| 22 | 172209614883062 |
| 23 | 845642719001622 |
[1,8,48,261,1358,6907,34683,172827,857077,4237179, 20904293,102987450,506887889,2493127016, 12256531946,60233878032,295941325816, 1453755559520,7140344796458,35067449154442, 172209614883062,845642719001622] |