n | a(n) |
---|---|
2 | 1 |
3 | 2 |
4 | 7 |
5 | 18 |
6 | 56 |
7 | 168 |
8 | 543 |
9 | 1792 |
10 | 6187 |
11 | 22088 |
12 | 81766 |
13 | 313224 |
14 | 1239764 |
15 | 5068320 |
16 | 21355894 |
17 | 92714368 |
18 | 413918310 |
19 | 1899260064 |
20 | 8941942444 |
21 | 43168351136 |
22 | 213385362136 |
23 | 1079240048256 |
24 | 5578228510556 |
25 | 29443746273792 |
26 | 158547033453372 |
27 | 870370433845888 |
28 | 4866859876496872 |
[1,2,7,18,56,168,543,1792,6187,22088,81766,313224, 1239764,5068320,21355894,92714368,413918310, 1899260064,8941942444,43168351136,213385362136, 1079240048256,5578228510556,29443746273792, 158547033453372,870370433845888,4866859876496872] |