n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 3 |
3 | 11 |
4 | 50 |
5 | 274 |
6 | 1764 |
7 | 13068 |
8 | 109584 |
9 | 1026576 |
10 | 10628640 |
11 | 120543840 |
12 | 1486442880 |
13 | 19802759040 |
14 | 283465647360 |
15 | 4339163001600 |
16 | 70734282393600 |
17 | 1223405590579200 |
18 | 22376988058521600 |
19 | 431565146817638400 |
20 | 8752948036761600000 |
21 | 186244810780170240000 |
[0,1,3,11,50,274,1764,13068,109584,1026576, 10628640,120543840,1486442880,19802759040, 283465647360,4339163001600,70734282393600, 1223405590579200,22376988058521600, 431565146817638400,8752948036761600000, 186244810780170240000] |