n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 1 |
3 | 3 |
4 | 6 |
5 | 15 |
6 | 42 |
7 | 109 |
8 | 320 |
9 | 979 |
10 | 3137 |
11 | 10603 |
12 | 37728 |
13 | 140423 |
14 | 546859 |
15 | 2220294 |
16 | 9374309 |
17 | 41059926 |
18 | 186149869 |
19 | 871717073 |
20 | 4208841555 |
21 | 20917405824 |
22 | 106849492793 |
[1,0,1,3,6,15,42,109,320,979,3137,10603,37728, 140423,546859,2220294,9374309,41059926,186149869, 871717073,4208841555,20917405824,106849492793] |