The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 15 |
| 3 | 280 |
| 4 | 9945 |
| 5 | 576576 |
| 6 | 49579075 |
| 7 | 5925744000 |
| 8 | 939536222625 |
| 9 | 190787784140800 |
| 10 | 48279601331512551 |
| 11 | 14894665739501184000 |
| 12 | 5502449072258318805625 |
| 13 | 2397950328737212204032000 |
[1,2,15,280,9945,576576,49579075,5925744000, 939536222625,190787784140800,48279601331512551, 14894665739501184000,5502449072258318805625, 2397950328737212204032000] |