n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 16 |
3 | 120 |
4 | 882 |
5 | 6468 |
6 | 47680 |
7 | 354224 |
8 | 2652688 |
9 | 20008864 |
10 | 151853312 |
11 | 1158365824 |
12 | 8873772392 |
13 | 68219456080 |
14 | 526025997824 |
15 | 4066475337152 |
16 | 31505967787522 |
17 | 244574907064964 |
18 | 1901855959279776 |
19 | 14811829930479600 |
20 | 115514550050260068 |
21 | 901993060739459720 |
[1,2,16,120,882,6468,47680,354224,2652688, 20008864,151853312,1158365824,8873772392, 68219456080,526025997824,4066475337152, 31505967787522,244574907064964,1901855959279776, 14811829930479600,115514550050260068, 901993060739459720] |