n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 4 |
3 | 12 |
4 | 36 |
5 | 106 |
6 | 249 |
7 | 613 |
8 | 1732 |
9 | 8028 |
10 | 23348 |
11 | 69370 |
12 | 210807 |
13 | 634839 |
14 | 1893582 |
15 | 5686389 |
16 | 17031777 |
17 | 51073675 |
18 | 153185957 |
19 | 459516225 |
20 | 1378707224 |
21 | 4135278456 |
[1,2,4,12,36,106,249,613,1732,8028,23348,69370, 210807,634839,1893582,5686389,17031777,51073675, 153185957,459516225,1378707224,4135278456] |