The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 25 |
| 5 | 71 |
| 6 | 360 |
| 7 | 1310 |
| 8 | 7195 |
| 9 | 35740 |
| 10 | 213318 |
| 11 | 1132154 |
| 12 | 8409475 |
| 13 | 50344672 |
| 14 | 366939569 |
| 15 | 2728237607 |
| 16 | 21375289293 |
| 17 | 159969524749 |
| 18 | 1462761108082 |
| 19 | 11896122581676 |
| 20 | 107011124829787 |
| 21 | 1031744001100166 |
| 22 | 9684995830526129 |
| 23 | 91735916202054984 |
| 24 | 1010641832989185386 |
| 25 | 10131466944871497886 |
[1,3,7,25,71,360,1310,7195,35740,213318,1132154, 8409475,50344672,366939569,2728237607,21375289293, 159969524749,1462761108082,11896122581676, 107011124829787,1031744001100166,9684995830526129, 91735916202054984,1010641832989185386, 10131466944871497886] |