The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 8 |
| 3 | 57 |
| 4 | 424 |
| 5 | 3425 |
| 6 | 30336 |
| 7 | 294553 |
| 8 | 3123632 |
| 9 | 36003969 |
| 10 | 448816600 |
| 11 | 6022033721 |
| 12 | 86587079448 |
| 13 | 1328753602657 |
| 14 | 21683227579664 |
| 15 | 375013198304025 |
| 16 | 6853321766162656 |
| 17 | 131976208783240193 |
| 18 | 2671430511854158632 |
| 19 | 56709161712552286009 |
| 20 | 1259836187316759240200 |
[1,8,57,424,3425,30336,294553,3123632,36003969, 448816600,6022033721,86587079448,1328753602657, 21683227579664,375013198304025,6853321766162656, 131976208783240193,2671430511854158632, 56709161712552286009,1259836187316759240200] |