n | a(n) |
---|---|
1 | 0 |
2 | 1 |
3 | 2 |
4 | 6 |
5 | 22 |
6 | 88 |
7 | 372 |
8 | 1636 |
9 | 7406 |
10 | 34276 |
11 | 161436 |
12 | 771238 |
13 | 3728168 |
14 | 18201830 |
15 | 89622696 |
16 | 444533010 |
17 | 2219057382 |
18 | 11139859864 |
19 | 56203325212 |
20 | 284828848740 |
21 | 1449270351504 |
[0,1,2,6,22,88,372,1636,7406,34276,161436,771238, 3728168,18201830,89622696,444533010,2219057382, 11139859864,56203325212,284828848740, 1449270351504] |