n | a(n) |
---|---|
1 | 0 |
2 | 1 |
3 | 1 |
4 | 7 |
5 | 18 |
6 | 80 |
7 | 284 |
8 | 1169 |
9 | 4628 |
10 | 19137 |
11 | 79165 |
12 | 333058 |
13 | 1410608 |
14 | 6029816 |
15 | 25941384 |
16 | 112315945 |
17 | 488862888 |
18 | 2138161043 |
19 | 9391903131 |
20 | 41414729419 |
21 | 183264846010 |
22 | 813564012660 |
23 | 3622193670040 |
24 | 16170171489820 |
25 | 72364908958800 |
26 | 324586284275500 |
27 | 1458976377988636 |
[0,1,1,7,18,80,284,1169,4628,19137,79165,333058, 1410608,6029816,25941384,112315945,488862888, 2138161043,9391903131,41414729419,183264846010, 813564012660,3622193670040,16170171489820, 72364908958800,324586284275500,1458976377988636] |