| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 63 |
| 4 | 736 |
| 5 | 10625 |
| 6 | 182736 |
| 7 | 3647119 |
| 8 | 82837504 |
| 9 | 2109289329 |
| 10 | 59500000000 |
| 11 | 1841557146671 |
| 12 | 62041198952448 |
| 13 | 2259914256880657 |
| 14 | 88499197217837056 |
| 15 | 3707501605224609375 |
| 16 | 165444235911082541056 |
| 17 | 7834451891982365825441 |
| 18 | 392371124973096027488256 |
[0,1,7,63,736,10625,182736,3647119,82837504, 2109289329,59500000000,1841557146671, 62041198952448,2259914256880657,88499197217837056, 3707501605224609375,165444235911082541056, 7834451891982365825441,392371124973096027488256] |