n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 9 |
3 | 24 |
4 | 66 |
5 | 180 |
6 | 468 |
7 | 1206 |
8 | 3150 |
9 | 7998 |
10 | 20124 |
11 | 50520 |
12 | 124044 |
13 | 303906 |
14 | 744870 |
15 | 1790226 |
16 | 4319322 |
17 | 10432044 |
18 | 24926934 |
19 | 59570514 |
20 | 142662384 |
21 | 339247320 |
22 | 807092274 |
23 | 1920506232 |
24 | 4543861644 |
[1,3,9,24,66,180,468,1206,3150,7998,20124,50520, 124044,303906,744870,1790226,4319322,10432044, 24926934,59570514,142662384,339247320,807092274, 1920506232,4543861644] |