The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 51 |
| 4 | 657 |
| 5 | 9722 |
| 6 | 166296 |
| 7 | 3253365 |
| 8 | 71905965 |
| 9 | 1775175455 |
| 10 | 48467529392 |
| 11 | 1451065354742 |
| 12 | 47289516677131 |
| 13 | 1667001471950287 |
| 14 | 63213921938077523 |
| 15 | 2566296044236261518 |
| 16 | 111065406214766719510 |
| 17 | 5105032675471072965466 |
| 18 | 248377281869637961805657 |
[1,1,5,51,657,9722,166296,3253365,71905965, 1775175455,48467529392,1451065354742, 47289516677131,1667001471950287,63213921938077523, 2566296044236261518,111065406214766719510, 5105032675471072965466,248377281869637961805657] |