n | a(n) |
---|---|
1 | 0 |
2 | 1 |
3 | 2 |
4 | 6 |
5 | 18 |
6 | 78 |
7 | 456 |
8 | 4299 |
9 | 68754 |
10 | 1990286 |
11 | 106088988 |
12 | 10454883132 |
13 | 1904236651216 |
14 | 641859005526860 |
15 | 401547534010157680 |
16 | 467956331904669136874 |
17 | 1019785644052109276678788 |
18 | 4171197546082606538129623140 |
[0,1,2,6,18,78,456,4299,68754,1990286,106088988, 10454883132,1904236651216,641859005526860, 401547534010157680,467956331904669136874, 1019785644052109276678788, 4171197546082606538129623140] |