n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 22 |
4 | 140 |
5 | 950 |
6 | 6692 |
7 | 48284 |
8 | 354216 |
9 | 2630310 |
10 | 19713188 |
11 | 148817524 |
12 | 1130011896 |
13 | 8621650492 |
14 | 66043991080 |
15 | 507628779896 |
16 | 3913088587472 |
17 | 30240258982662 |
18 | 234210742764964 |
19 | 1817484391184900 |
20 | 14128074297880536 |
[1,4,22,140,950,6692,48284,354216,2630310, 19713188,148817524,1130011896,8621650492, 66043991080,507628779896,3913088587472, 30240258982662,234210742764964,1817484391184900, 14128074297880536] |