n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 1 |
3 | 8 |
4 | 18 |
5 | 184 |
6 | 660 |
7 | 8448 |
8 | 42000 |
9 | 648576 |
10 | 4142880 |
11 | 74972160 |
12 | 586776960 |
13 | 12174658560 |
14 | 113020427520 |
15 | 2643856588800 |
16 | 28432576972800 |
17 | 740051782041600 |
18 | 9056055981772800 |
19 | 259500083163955200 |
20 | 3562946373482496000 |
[0,1,1,8,18,184,660,8448,42000,648576,4142880, 74972160,586776960,12174658560,113020427520, 2643856588800,28432576972800,740051782041600, 9056055981772800,259500083163955200, 3562946373482496000] |