n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 1 |
5 | 1 |
6 | 4 |
7 | 5 |
8 | 16 |
9 | 37 |
10 | 120 |
11 | 344 |
12 | 1175 |
13 | 3807 |
14 | 13224 |
15 | 45645 |
16 | 161705 |
17 | 575325 |
18 | 2074088 |
19 | 7521818 |
20 | 27502445 |
21 | 101134999 |
22 | 374128188 |
[0,0,1,1,1,4,5,16,37,120,344,1175,3807,13224, 45645,161705,575325,2074088,7521818,27502445, 101134999,374128188] |