n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 14 |
4 | 60 |
5 | 252 |
6 | 1212 |
7 | 5880 |
8 | 30904 |
9 | 166976 |
10 | 952456 |
11 | 5587840 |
12 | 34217216 |
13 | 215204960 |
14 | 1401551376 |
15 | 9360467760 |
16 | 64384034784 |
17 | 453328282624 |
18 | 3274696185568 |
19 | 24173219998912 |
20 | 182546586425408 |
[1,4,14,60,252,1212,5880,30904,166976,952456, 5587840,34217216,215204960,1401551376,9360467760, 64384034784,453328282624,3274696185568, 24173219998912,182546586425408] |