The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 3 |
| 3 | 6 |
| 4 | 21 |
| 5 | 159 |
| 6 | 1002 |
| 7 | 5426 |
| 8 | 32678 |
| 9 | 213283 |
| 10 | 1389400 |
| 11 | 9052394 |
| 12 | 60114080 |
| 13 | 406302200 |
| 14 | 2775970886 |
| 15 | 19129099772 |
| 16 | 132872261760 |
[3,6,21,159,1002,5426,32678,213283,1389400, 9052394,60114080,406302200,2775970886,19129099772, 132872261760] |