n | a(n) |
---|---|
2 | 1 |
3 | 1 |
4 | 3 |
5 | 7 |
6 | 20 |
7 | 55 |
8 | 162 |
9 | 477 |
10 | 1450 |
11 | 4446 |
12 | 13858 |
13 | 43589 |
14 | 138515 |
15 | 443487 |
16 | 1430261 |
17 | 4640312 |
18 | 15137893 |
19 | 49620637 |
20 | 163360133 |
21 | 539904503 |
22 | 1790699059 |
23 | 5958280016 |
24 | 19883532941 |
25 | 66532519727 |
26 | 223177199775 |
27 | 750340752081 |
28 | 2528058240115 |
[1,1,3,7,20,55,162,477,1450,4446,13858,43589, 138515,443487,1430261,4640312,15137893,49620637, 163360133,539904503,1790699059,5958280016, 19883532941,66532519727,223177199775,750340752081, 2528058240115] |