n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 30 |
4 | 320 |
5 | 4400 |
6 | 74016 |
7 | 1472240 |
8 | 33800192 |
9 | 879646464 |
10 | 25589632000 |
11 | 822867814912 |
12 | 28982612385792 |
13 | 1109640105852928 |
14 | 45884917741981696 |
15 | 2038015221365667840 |
16 | 96765606087737999360 |
17 | 4890992991269273403392 |
18 | 262201755871367895711744 |
19 | 14859866059895961631981568 |
20 | 887693530413229611155456000 |
[1,1,4,30,320,4400,74016,1472240,33800192, 879646464,25589632000,822867814912,28982612385792, 1109640105852928,45884917741981696, 2038015221365667840,96765606087737999360, 4890992991269273403392,262201755871367895711744, 14859866059895961631981568, 887693530413229611155456000] |