n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 0 |
4 | 0 |
5 | 2 |
6 | 4 |
7 | 18 |
8 | 48 |
9 | 156 |
10 | 472 |
11 | 1526 |
12 | 4852 |
13 | 16000 |
14 | 52940 |
15 | 178276 |
16 | 605520 |
17 | 2079862 |
18 | 7201084 |
19 | 25138878 |
20 | 88358520 |
21 | 312576996 |
22 | 1112087012 |
23 | 3977502766 |
24 | 14294093652 |
25 | 51596165872 |
26 | 186997738504 |
27 | 680272334202 |
28 | 2483340387644 |
29 | 9094756956908 |
[1,0,0,0,2,4,18,48,156,472,1526,4852,16000,52940, 178276,605520,2079862,7201084,25138878,88358520, 312576996,1112087012,3977502766,14294093652, 51596165872,186997738504,680272334202, 2483340387644,9094756956908] |