The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 48 |
| 7 | 708 |
| 8 | 9807 |
| 9 | 119436 |
| 10 | 1355400 |
| 11 | 14561360 |
| 12 | 150429819 |
[0,0,0,0,4,48,708,9807,119436,1355400,14561360, 150429819] |