n | a(n) |
---|---|
2 | 1 |
3 | 0 |
4 | 1 |
5 | 2 |
6 | 4 |
7 | 10 |
8 | 23 |
9 | 56 |
10 | 138 |
11 | 344 |
12 | 870 |
13 | 2220 |
14 | 5716 |
15 | 14828 |
16 | 38717 |
17 | 101682 |
18 | 268416 |
19 | 711810 |
20 | 1895432 |
21 | 5066030 |
22 | 13586082 |
23 | 36547534 |
24 | 98593064 |
25 | 266661162 |
26 | 722953814 |
27 | 1964358938 |
28 | 5348367006 |
29 | 14589803090 |
30 | 39870312218 |
31 | 109136843138 |
[1,0,1,2,4,10,23,56,138,344,870,2220,5716,14828, 38717,101682,268416,711810,1895432,5066030, 13586082,36547534,98593064,266661162,722953814, 1964358938,5348367006,14589803090,39870312218, 109136843138] |