n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 1 |
4 | 2 |
5 | 9 |
6 | 22 |
7 | 109 |
8 | 390 |
9 | 2249 |
10 | 10006 |
11 | 53540 |
12 | 207218 |
13 | 967733 |
14 | 3587686 |
15 | 14902072 |
16 | 56388126 |
17 | 220066307 |
18 | 867528322 |
19 | 3324603126 |
20 | 13719108983 |
[1,0,1,2,9,22,109,390,2249,10006,53540,207218, 967733,3587686,14902072,56388126,220066307, 867528322,3324603126,13719108983] |