The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 63 |
| 4 | 988 |
| 5 | 20725 |
| 6 | 546246 |
| 7 | 17364445 |
| 8 | 646910328 |
| 9 | 27652214313 |
| 10 | 1334291800330 |
| 11 | 71749167806041 |
| 12 | 4255000637001588 |
| 13 | 275904038948566093 |
| 14 | 19420072633921942542 |
| 15 | 1474700254793433800805 |
| 16 | 120174737260376219862256 |
| 17 | 10461031446553525766071249 |
| 18 | 968785652772129485926955538 |
[1,1,6,63,988,20725,546246,17364445,646910328, 27652214313,1334291800330,71749167806041, 4255000637001588,275904038948566093, 19420072633921942542,1474700254793433800805, 120174737260376219862256, 10461031446553525766071249, 968785652772129485926955538] |