n | a(n) |
---|---|
1 | 0 |
2 | 1 |
3 | 3 |
4 | 10 |
5 | 25 |
6 | 78 |
7 | 283 |
8 | 906 |
9 | 3044 |
10 | 10920 |
11 | 37920 |
12 | 135182 |
13 | 487555 |
14 | 1764216 |
15 | 6415902 |
16 | 23585285 |
17 | 86789112 |
18 | 320972293 |
19 | 1192327462 |
20 | 4441973622 |
[0,1,3,10,25,78,283,906,3044,10920,37920,135182, 487555,1764216,6415902,23585285,86789112, 320972293,1192327462,4441973622] |