The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 68 |
| 4 | 2120 |
| 5 | 97000 |
| 6 | 5872480 |
| 7 | 443112320 |
| 8 | 40082987840 |
| 9 | 4229690684800 |
| 10 | 510256604704000 |
| 11 | 69286724339571200 |
| 12 | 10460172341107596800 |
| 13 | 1738224199173119257600 |
| 14 | 315317775853369569280000 |
| 15 | 62006120216315851896320000 |
| 16 | 13139441006285026849095680000 |
| 17 | 2984985630578153138966149120000 |
[1,4,68,2120,97000,5872480,443112320,40082987840, 4229690684800,510256604704000,69286724339571200, 10460172341107596800,1738224199173119257600, 315317775853369569280000, 62006120216315851896320000, 13139441006285026849095680000, 2984985630578153138966149120000] |