n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 16 |
4 | 68 |
5 | 304 |
6 | 1412 |
7 | 6752 |
8 | 33028 |
9 | 164512 |
10 | 831620 |
11 | 4255728 |
12 | 22004292 |
13 | 114781008 |
14 | 603308292 |
15 | 3192216000 |
16 | 16989553668 |
17 | 90890869312 |
18 | 488500827908 |
19 | 2636405463248 |
20 | 14281895003716 |
21 | 77631035881072 |
22 | 423282220216964 |
23 | 2314491475510816 |
24 | 12688544297945348 |
[1,1,4,16,68,304,1412,6752,33028,164512,831620, 4255728,22004292,114781008,603308292,3192216000, 16989553668,90890869312,488500827908, 2636405463248,14281895003716,77631035881072, 423282220216964,2314491475510816, 12688544297945348] |