n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 6 |
5 | 18 |
6 | 55 |
7 | 147 |
8 | 405 |
9 | 1083 |
10 | 2961 |
11 | 8043 |
12 | 22182 |
13 | 61278 |
14 | 170883 |
15 | 477910 |
16 | 1344825 |
17 | 3795750 |
18 | 10757763 |
19 | 30572427 |
20 | 87146139 |
21 | 248991674 |
22 | 713088309 |
23 | 2046303339 |
24 | 5883410760 |
25 | 16944543792 |
26 | 48879708297 |
[0,0,1,6,18,55,147,405,1083,2961,8043,22182,61278, 170883,477910,1344825,3795750,10757763,30572427, 87146139,248991674,713088309,2046303339, 5883410760,16944543792,48879708297] |