n | a(n) |
---|---|
3 | 1 |
4 | 4 |
5 | 12 |
6 | 36 |
7 | 105 |
8 | 306 |
9 | 889 |
10 | 2584 |
11 | 7515 |
12 | 21880 |
13 | 63778 |
14 | 186132 |
15 | 543855 |
16 | 1590876 |
17 | 4658580 |
18 | 13655472 |
19 | 40065243 |
20 | 117654876 |
21 | 345786396 |
22 | 1017040380 |
23 | 2993498739 |
24 | 8816790906 |
25 | 25984489545 |
26 | 76625467128 |
27 | 226085062525 |
28 | 667415280376 |
29 | 1971209865654 |
30 | 5824651789852 |
[1,4,12,36,105,306,889,2584,7515,21880,63778, 186132,543855,1590876,4658580,13655472,40065243, 117654876,345786396,1017040380,2993498739, 8816790906,25984489545,76625467128,226085062525, 667415280376,1971209865654,5824651789852] |