n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 3 |
4 | 20 |
5 | 132 |
6 | 1888 |
7 | 20128 |
8 | 584000 |
9 | 17102016 |
10 | 553895936 |
11 | 11616690176 |
12 | 743337949184 |
13 | 19467186157568 |
14 | 999551845713920 |
15 | 66437400489711616 |
16 | 10253161206302064640 |
17 | 388089999627661557760 |
18 | 53727789519052432998400 |
19 | 2325767421950553303285760 |
20 | 365546030278816140131041280 |
[1,1,1,3,20,132,1888,20128,584000,17102016, 553895936,11616690176,743337949184,19467186157568, 999551845713920,66437400489711616, 10253161206302064640,388089999627661557760, 53727789519052432998400,2325767421950553303285760, 365546030278816140131041280] |