The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 840 |
| 3 | 2560 |
| 4 | 26376 |
| 5 | 30720 |
| 6 | 204960 |
| 7 | 168960 |
| 8 | 843528 |
| 9 | 593920 |
| 10 | 2625840 |
| 11 | 1605120 |
| 12 | 6435744 |
| 13 | 3717120 |
| 14 | 14118720 |
| 15 | 7633920 |
| 16 | 26992392 |
| 17 | 14192640 |
| 18 | 49806120 |
| 19 | 24752640 |
| 20 | 82451376 |
[1,0,840,2560,26376,30720,204960,168960,843528, 593920,2625840,1605120,6435744,3717120,14118720, 7633920,26992392,14192640,49806120,24752640, 82451376] |