n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 20 |
4 | 112 |
5 | 660 |
6 | 3976 |
7 | 24180 |
8 | 147648 |
9 | 903140 |
10 | 5528504 |
11 | 33853220 |
12 | 207325392 |
13 | 1269787060 |
14 | 7777149416 |
15 | 47633751380 |
16 | 291750220768 |
17 | 1786933908740 |
18 | 10944758154264 |
19 | 67035370422020 |
20 | 410583912229872 |
21 | 2514779283989460 |
22 | 15402734618128456 |
23 | 94339983758166580 |
[1,4,20,112,660,3976,24180,147648,903140,5528504, 33853220,207325392,1269787060,7777149416, 47633751380,291750220768,1786933908740, 10944758154264,67035370422020,410583912229872, 2514779283989460,15402734618128456, 94339983758166580] |