n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 20 |
4 | 223 |
5 | 3227 |
6 | 77194 |
7 | 2097080 |
8 | 57796870 |
9 | 1502295684 |
10 | 36065804158 |
11 | 795109767172 |
12 | 16115614918786 |
13 | 301341514055753 |
14 | 5220182848555434 |
15 | 84132279974374399 |
[1,1,4,20,223,3227,77194,2097080,57796870, 1502295684,36065804158,795109767172, 16115614918786,301341514055753,5220182848555434, 84132279974374399] |