n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 4 |
3 | 12 |
4 | 56 |
5 | 192 |
6 | 756 |
7 | 2748 |
8 | 10408 |
9 | 38544 |
10 | 144452 |
11 | 537900 |
12 | 2009880 |
13 | 7496160 |
14 | 27985684 |
15 | 104424732 |
16 | 389756936 |
17 | 1454515632 |
18 | 5428480356 |
19 | 20259056268 |
20 | 75608443768 |
21 | 282173320704 |
22 | 1053087635252 |
23 | 3930171627900 |
24 | 14667610061160 |
25 | 54740246247120 |
26 | 204293419666564 |
[0,0,4,12,56,192,756,2748,10408,38544,144452, 537900,2009880,7496160,27985684,104424732, 389756936,1454515632,5428480356,20259056268, 75608443768,282173320704,1053087635252, 3930171627900,14667610061160,54740246247120, 204293419666564] |