The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 46 |
| 6 | 2284 |
| 7 | 1405428 |
| 8 | 229798671816 |
| 9 | 423295097006496421879 |
[1,0,1,4,46,2284,1405428,229798671816, 423295097006496421879] |