n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 2 |
3 | 4 |
4 | 12 |
5 | 36 |
6 | 142 |
7 | 624 |
8 | 3192 |
9 | 18256 |
10 | 116282 |
11 | 814144 |
12 | 6219972 |
13 | 51475776 |
14 | 458790022 |
15 | 4381112064 |
16 | 44625674352 |
17 | 482962852096 |
18 | 5534347077362 |
19 | 66942218896384 |
20 | 852334810990332 |
21 | 11394877025289216 |
[0,1,2,4,12,36,142,624,3192,18256,116282,814144, 6219972,51475776,458790022,4381112064,44625674352, 482962852096,5534347077362,66942218896384, 852334810990332,11394877025289216] |