The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 4800 |
| 8 | 34944 |
| 9 | 284112 |
| 10 | 2610000 |
| 11 | 25619416 |
| 12 | 281967300 |
| 13 | 3260094820 |
| 14 | 40530153902 |
| 15 | 544648728448 |
| 16 | 7866179354326 |
[1,2,6,24,120,720,4800,34944,284112,2610000, 25619416,281967300,3260094820,40530153902, 544648728448,7866179354326] |