n | a(n) |
---|---|
1 | 2 |
2 | 20 |
3 | 120 |
4 | 698 |
5 | 4080 |
6 | 24074 |
7 | 141856 |
8 | 833758 |
9 | 4909544 |
10 | 28899922 |
11 | 170120402 |
12 | 1001361542 |
13 | 5894102732 |
14 | 34694985108 |
15 | 204224876622 |
16 | 1202124327402 |
17 | 7076038423114 |
18 | 41651567268298 |
19 | 245173129915012 |
20 | 1443158678807678 |
[2,20,120,698,4080,24074,141856,833758,4909544, 28899922,170120402,1001361542,5894102732, 34694985108,204224876622,1202124327402, 7076038423114,41651567268298,245173129915012, 1443158678807678] |