n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 2 |
4 | 6 |
5 | 20 |
6 | 90 |
7 | 550 |
8 | 3512 |
9 | 25378 |
10 | 200558 |
11 | 1778156 |
12 | 17016488 |
13 | 177741892 |
14 | 1984308356 |
15 | 23873823014 |
16 | 304944376412 |
17 | 4155112842840 |
[1,0,2,6,20,90,550,3512,25378,200558,1778156, 17016488,177741892,1984308356,23873823014, 304944376412,4155112842840] |