n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 0 |
3 | 1 |
4 | 2 |
5 | 6 |
6 | 18 |
7 | 57 |
8 | 186 |
9 | 622 |
10 | 2120 |
11 | 7338 |
12 | 25724 |
13 | 91144 |
14 | 325878 |
15 | 1174281 |
16 | 4260282 |
17 | 15548694 |
18 | 57048048 |
19 | 210295326 |
20 | 778483932 |
21 | 2892818244 |
22 | 10786724388 |
23 | 40347919626 |
24 | 151355847012 |
25 | 569274150156 |
26 | 2146336125648 |
27 | 8110508473252 |
28 | 30711521221376 |
[0,1,0,1,2,6,18,57,186,622,2120,7338,25724,91144, 325878,1174281,4260282,15548694,57048048, 210295326,778483932,2892818244,10786724388, 40347919626,151355847012,569274150156, 2146336125648,8110508473252,30711521221376] |