n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 4 |
4 | 20 |
5 | 132 |
6 | 1076 |
7 | 10404 |
8 | 116180 |
9 | 1469892 |
10 | 20766836 |
11 | 323924964 |
12 | 5527326740 |
13 | 102396386052 |
14 | 2046350191796 |
15 | 43876822764324 |
16 | 1004631156809300 |
17 | 24463049576172612 |
18 | 631213045618035956 |
19 | 17203155473859536484 |
[0,0,4,20,132,1076,10404,116180,1469892,20766836, 323924964,5527326740,102396386052,2046350191796, 43876822764324,1004631156809300,24463049576172612, 631213045618035956,17203155473859536484] |