The OEIS is supported by the many generous donors to the OEIS Foundation.
A218296 as a simple table
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 30 |
| 4 | 352 |
| 5 | 5560 |
| 6 | 109056 |
| 7 | 2540720 |
| 8 | 68401152 |
| 9 | 2087897472 |
| 10 | 71236526080 |
| 11 | 2686375597312 |
| 12 | 110951893303296 |
| 13 | 4980913763830784 |
| 14 | 241491517062512640 |
| 15 | 12575483733378816000 |
| 16 | 700015678015053758464 |
| 17 | 41480146826887546372096 |
| 18 | 2606901492484549499682816 |
[1,1,4,30,352,5560,109056,2540720,68401152, 2087897472,71236526080,2686375597312, 110951893303296,4980913763830784, 241491517062512640,12575483733378816000, 700015678015053758464,41480146826887546372096, 2606901492484549499682816] |