n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 0 |
3 | 4 |
4 | 6 |
5 | 30 |
6 | 348 |
7 | 1580 |
8 | 12516 |
9 | 114884 |
10 | 1375776 |
11 | 12239280 |
12 | 160067160 |
13 | 1966619512 |
14 | 28104385008 |
15 | 428735710000 |
16 | 6769181533968 |
17 | 110402248461840 |
18 | 2070626881211136 |
19 | 38342125010072384 |
20 | 764180537501729376 |
21 | 16185744192232110560 |
22 | 354756690964676468160 |
[1,1,0,4,6,30,348,1580,12516,114884,1375776, 12239280,160067160,1966619512,28104385008, 428735710000,6769181533968,110402248461840, 2070626881211136,38342125010072384, 764180537501729376,16185744192232110560, 354756690964676468160] |