n | a(n) |
---|---|
2 | 0 |
3 | 2 |
4 | 2 |
5 | 12 |
6 | 20 |
7 | 88 |
8 | 180 |
9 | 716 |
10 | 1648 |
11 | 6244 |
12 | 15512 |
13 | 57188 |
14 | 149892 |
15 | 543324 |
16 | 1481636 |
17 | 5310764 |
18 | 4930380 |
19 | 53102508 |
20 | 152935148 |
21 | 540918660 |
22 | 1588618212 |
23 | 5595773136 |
24 | 16701973552 |
[0,2,2,12,20,88,180,716,1648,6244,15512,57188, 149892,543324,1481636,5310764,4930380,53102508, 152935148,540918660,1588618212,5595773136, 16701973552] |