The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 37 |
| 5 | 1204 |
| 6 | 21029921 |
| 7 | 425355555167420 |
| 8 | 439183524292095499600664584581 |
| 9 | 240317442633783387248198509182959563857071128274317237128901 |
[1,1,3,37,1204,21029921,425355555167420, 439183524292095499600664584581, 24031744263378338724819850918295956385707112827431\ 7237128901] |