n | a(n) |
---|---|
1 | 0 |
2 | 2 |
3 | 2 |
4 | 40 |
5 | 90 |
6 | 1336 |
7 | 3458 |
8 | 44516 |
9 | 126476 |
10 | 1527344 |
11 | 4599422 |
12 | 53131172 |
13 | 167316392 |
14 | 1872027432 |
15 | 6086187592 |
16 | 66611566008 |
17 | 221500197840 |
18 | 2388653206624 |
19 | 8068017360224 |
20 | 86178588357352 |
21 | 294198667299936 |
22 | 3124170165050528 |
[0,2,2,40,90,1336,3458,44516,126476,1527344, 4599422,53131172,167316392,1872027432,6086187592, 66611566008,221500197840,2388653206624, 8068017360224,86178588357352,294198667299936, 3124170165050528] |