The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 30 |
| 4 | 756 |
| 5 | 75600 |
| 6 | 199584 |
| 7 | 54486432000 |
| 8 | 2421619200 |
| 9 | 151227648000 |
| 10 | 5913303492096000 |
| 11 | 5203707073044480000 |
| 12 | 512936840057241600000 |
| 13 | 5041143264082570444800000 |
| 14 | 1238175538546596249600000 |
| 15 | 11695452372671563431936000000 |
| 16 | 33500453776280426294437478400000 |
| 17 | 44295044437526341433756221440000000 |
[1,1,1,30,756,75600,199584,54486432000,2421619200, 151227648000,5913303492096000,5203707073044480000, 512936840057241600000,5041143264082570444800000, 1238175538546596249600000, 11695452372671563431936000000, 33500453776280426294437478400000, 44295044437526341433756221440000000] |