n | a(n) |
---|---|
1 | 6 |
2 | 15 |
3 | 90 |
4 | 351 |
5 | 2106 |
6 | 10935 |
7 | 65610 |
8 | 378351 |
9 | 2270106 |
10 | 13482855 |
11 | 80897130 |
12 | 484142751 |
13 | 2904856506 |
14 | 17417978775 |
15 | 104507872650 |
16 | 626946793551 |
17 | 3761680761306 |
18 | 22569180586695 |
19 | 135415083520170 |
20 | 812482365290751 |
21 | 4874894191744506 |
[6,15,90,351,2106,10935,65610,378351,2270106, 13482855,80897130,484142751,2904856506, 17417978775,104507872650,626946793551, 3761680761306,22569180586695,135415083520170, 812482365290751,4874894191744506] |