n | a(n) |
---|---|
0 | 1 |
1 | 6 |
2 | 30 |
3 | 150 |
4 | 750 |
5 | 3726 |
6 | 18438 |
7 | 90966 |
8 | 447918 |
9 | 2201622 |
10 | 10809006 |
11 | 52999446 |
12 | 259668942 |
13 | 1271054982 |
14 | 6218232414 |
15 | 30399142614 |
[1,6,30,150,750,3726,18438,90966,447918,2201622, 10809006,52999446,259668942,1271054982,6218232414, 30399142614] |