n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 15 |
4 | 56 |
5 | 209 |
6 | 780 |
7 | 2912 |
8 | 10880 |
9 | 40698 |
10 | 152456 |
11 | 572033 |
12 | 2150040 |
13 | 8095425 |
14 | 30535260 |
15 | 115377660 |
16 | 436698240 |
17 | 1655607390 |
18 | 6286707000 |
19 | 23908446510 |
20 | 91057063344 |
21 | 347281885818 |
22 | 1326262602104 |
23 | 5071418015120 |
24 | 19415851639296 |
25 | 74419447792340 |
[1,4,15,56,209,780,2912,10880,40698,152456,572033, 2150040,8095425,30535260,115377660,436698240, 1655607390,6286707000,23908446510,91057063344, 347281885818,1326262602104,5071418015120, 19415851639296,74419447792340] |