n | a(n) |
---|---|
1 | 2 |
2 | 20 |
3 | 120 |
4 | 698 |
5 | 4078 |
6 | 24032 |
7 | 141460 |
8 | 830652 |
9 | 4886324 |
10 | 28734972 |
11 | 168979540 |
12 | 993659990 |
13 | 5842982750 |
14 | 34359849144 |
15 | 202051334982 |
16 | 1188148848850 |
17 | 6986829817634 |
18 | 41085617221494 |
19 | 241601571059434 |
20 | 1420723058603468 |
[2,20,120,698,4078,24032,141460,830652,4886324, 28734972,168979540,993659990,5842982750, 34359849144,202051334982,1188148848850, 6986829817634,41085617221494,241601571059434, 1420723058603468] |