n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 4 |
4 | 24 |
5 | 100 |
6 | 360 |
7 | 1204 |
8 | 3864 |
9 | 12100 |
10 | 37320 |
11 | 114004 |
12 | 346104 |
13 | 1046500 |
14 | 3155880 |
15 | 9500404 |
16 | 28566744 |
17 | 85831300 |
18 | 257756040 |
19 | 773792404 |
20 | 2322425784 |
21 | 6969374500 |
22 | 20912317800 |
23 | 62745342004 |
24 | 188252803224 |
25 | 564791964100 |
26 | 1694443001160 |
27 | 5083463221204 |
28 | 15250658099064 |
[0,0,4,24,100,360,1204,3864,12100,37320,114004, 346104,1046500,3155880,9500404,28566744,85831300, 257756040,773792404,2322425784,6969374500, 20912317800,62745342004,188252803224,564791964100, 1694443001160,5083463221204,15250658099064] |