n | a(n) |
---|---|
2 | 1 |
3 | 2 |
4 | 7 |
5 | 20 |
6 | 60 |
7 | 176 |
8 | 517 |
9 | 1512 |
10 | 4415 |
11 | 12870 |
12 | 37477 |
13 | 109044 |
14 | 317109 |
15 | 921870 |
16 | 2679510 |
17 | 7787904 |
18 | 22636503 |
19 | 65804638 |
20 | 191332945 |
21 | 556456060 |
22 | 1618813834 |
23 | 4710869108 |
24 | 13713658368 |
25 | 39935698400 |
26 | 116340344575 |
27 | 339050396646 |
28 | 988474306017 |
[1,2,7,20,60,176,517,1512,4415,12870,37477,109044, 317109,921870,2679510,7787904,22636503,65804638, 191332945,556456060,1618813834,4710869108, 13713658368,39935698400,116340344575,339050396646, 988474306017] |