n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 112 |
4 | 664 |
5 | 4064 |
6 | 25376 |
7 | 160640 |
8 | 1027168 |
9 | 6618496 |
10 | 42904960 |
11 | 279503360 |
12 | 1828222720 |
13 | 11999226880 |
14 | 78984381440 |
15 | 521218322432 |
16 | 3447059138048 |
17 | 22840932997120 |
18 | 151607254267904 |
19 | 1007830488424448 |
20 | 6708862677274624 |
[1,4,20,112,664,4064,25376,160640,1027168,6618496, 42904960,279503360,1828222720,11999226880, 78984381440,521218322432,3447059138048, 22840932997120,151607254267904,1007830488424448, 6708862677274624] |