n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 0 |
5 | 0 |
6 | 2 |
7 | 4 |
8 | 15 |
9 | 36 |
10 | 108 |
11 | 276 |
12 | 771 |
13 | 2044 |
14 | 5622 |
15 | 15204 |
16 | 41835 |
17 | 114708 |
18 | 317382 |
19 | 879008 |
20 | 2447951 |
21 | 6833084 |
22 | 19146910 |
23 | 53786076 |
24 | 151537847 |
25 | 427946916 |
26 | 1211440440 |
27 | 3436543336 |
28 | 9768382171 |
29 | 27817787344 |
30 | 79356481542 |
[0,0,0,0,0,2,4,15,36,108,276,771,2044,5622,15204, 41835,114708,317382,879008,2447951,6833084, 19146910,53786076,151537847,427946916,1211440440, 3436543336,9768382171,27817787344,79356481542] |