n | a(n) |
---|---|
2 | 1 |
3 | 4 |
4 | 22 |
5 | 124 |
6 | 726 |
7 | 4352 |
8 | 26614 |
9 | 165204 |
10 | 1037672 |
11 | 6580424 |
12 | 42062040 |
13 | 270661328 |
14 | 1751614248 |
15 | 11391756176 |
16 | 74406502814 |
17 | 487838450116 |
18 | 3209229661682 |
19 | 21175301453040 |
20 | 140097533633112 |
21 | 929160187609096 |
[1,4,22,124,726,4352,26614,165204,1037672,6580424, 42062040,270661328,1751614248,11391756176, 74406502814,487838450116,3209229661682, 21175301453040,140097533633112,929160187609096] |