n | a(n) |
---|---|
1 | 2 |
2 | 6 |
3 | 20 |
4 | 60 |
5 | 208 |
6 | 624 |
7 | 2080 |
8 | 6240 |
9 | 18720 |
10 | 58240 |
11 | 176000 |
12 | 529408 |
13 | 1593344 |
14 | 4780032 |
15 | 14344192 |
16 | 43040768 |
17 | 129138688 |
18 | 387416064 |
19 | 1162248192 |
20 | 3486777344 |
21 | 10460332032 |
22 | 31380996096 |
23 | 94142988288 |
24 | 282428964864 |
25 | 847286894592 |
26 | 2541860683776 |
27 | 7625582051328 |
[2,6,20,60,208,624,2080,6240,18720,58240,176000, 529408,1593344,4780032,14344192,43040768, 129138688,387416064,1162248192,3486777344, 10460332032,31380996096,94142988288,282428964864, 847286894592,2541860683776,7625582051328] |