n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 2 |
3 | 4 |
4 | 12 |
5 | 32 |
6 | 108 |
7 | 336 |
8 | 1036 |
9 | 3120 |
10 | 9540 |
11 | 29244 |
12 | 89768 |
13 | 274788 |
14 | 840936 |
15 | 2573972 |
16 | 7881922 |
17 | 24135000 |
18 | 73897320 |
19 | 226249264 |
20 | 692714696 |
21 | 2120941424 |
22 | 6493883944 |
23 | 19882820480 |
24 | 60876609464 |
25 | 186390208744 |
26 | 570684661408 |
27 | 1747307671896 |
28 | 5349860697088 |
[0,0,2,4,12,32,108,336,1036,3120,9540,29244,89768, 274788,840936,2573972,7881922,24135000,73897320, 226249264,692714696,2120941424,6493883944, 19882820480,60876609464,186390208744,570684661408, 1747307671896,5349860697088] |