n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 1 |
4 | 4 |
5 | 10 |
6 | 40 |
7 | 171 |
8 | 831 |
9 | 4147 |
10 | 21822 |
11 | 117062 |
12 | 642600 |
13 | 3582322 |
14 | 20256885 |
15 | 115888201 |
16 | 669911568 |
17 | 3907720521 |
18 | 22979343010 |
19 | 136107859377 |
20 | 811430160282 |
21 | 4866004426320 |
22 | 29337068299728 |
23 | 177738920836446 |
24 | 1081668278379000 |
25 | 6609923004626478 |
26 | 40546403939165805 |
[1,1,1,4,10,40,171,831,4147,21822,117062,642600, 3582322,20256885,115888201,669911568,3907720521, 22979343010,136107859377,811430160282, 4866004426320,29337068299728,177738920836446, 1081668278379000,6609923004626478, 40546403939165805] |