n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 2 |
4 | 4 |
5 | 14 |
6 | 40 |
7 | 120 |
8 | 352 |
9 | 1032 |
10 | 3008 |
11 | 8736 |
12 | 25280 |
13 | 72928 |
14 | 209792 |
15 | 601984 |
16 | 1723392 |
17 | 4923520 |
18 | 14039040 |
19 | 39961088 |
20 | 113562624 |
21 | 322244096 |
22 | 913131520 |
23 | 2584180736 |
24 | 7304519680 |
25 | 20624050176 |
26 | 58170228736 |
27 | 163908034560 |
28 | 461421658112 |
[0,0,2,4,14,40,120,352,1032,3008,8736,25280,72928, 209792,601984,1723392,4923520,14039040,39961088, 113562624,322244096,913131520,2584180736, 7304519680,20624050176,58170228736,163908034560, 461421658112] |