n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 1 |
4 | 4 |
5 | 8 |
6 | 38 |
7 | 266 |
8 | 1680 |
9 | 10668 |
10 | 87444 |
11 | 1057140 |
12 | 10108644 |
13 | 114112320 |
14 | 1404689244 |
15 | 20654453736 |
16 | 294649177704 |
17 | 4556106886632 |
18 | 76389128377296 |
19 | 1363358922375072 |
20 | 25400563124152944 |
21 | 497084494996824840 |
[1,1,1,4,8,38,266,1680,10668,87444,1057140, 10108644,114112320,1404689244,20654453736, 294649177704,4556106886632,76389128377296, 1363358922375072,25400563124152944, 497084494996824840] |