The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 42 |
| 4 | 793 |
| 5 | 32276 |
| 6 | 2592379 |
| 7 | 423445648 |
| 8 | 145596625120 |
| 9 | 102532694528027 |
[1,4,42,793,32276,2592379,423445648,145596625120, 102532694528027] |