n | a(n) |
---|---|
1 | 0 |
2 | 2 |
3 | 6 |
4 | 18 |
5 | 50 |
6 | 290 |
7 | 2582 |
8 | 20462 |
9 | 23870 |
10 | 26342 |
11 | 31938 |
12 | 38122 |
13 | 65034 |
14 | 70130 |
15 | 245538 |
16 | 851878 |
17 | 1052422 |
18 | 1496566 |
19 | 5380542 |
20 | 8431178 |
[0,2,6,18,50,290,2582,20462,23870,26342,31938, 38122,65034,70130,245538,851878,1052422,1496566, 5380542,8431178] |