n | a(n) |
---|---|
0 | 0 |
1 | 2 |
2 | 4 |
3 | 22 |
4 | 56 |
5 | 250 |
6 | 732 |
7 | 2926 |
8 | 9264 |
9 | 34866 |
10 | 115316 |
11 | 419846 |
12 | 1422824 |
13 | 5086122 |
14 | 17471692 |
15 | 61823966 |
16 | 213983072 |
17 | 752927074 |
18 | 2616950756 |
19 | 9179311350 |
20 | 31978941080 |
21 | 111975792474 |
22 | 390606950844 |
23 | 1366410142030 |
24 | 4769896907152 |
25 | 16676981234578 |
26 | 58239643256916 |
[0,2,4,22,56,250,732,2926,9264,34866,115316, 419846,1422824,5086122,17471692,61823966, 213983072,752927074,2616950756,9179311350, 31978941080,111975792474,390606950844, 1366410142030,4769896907152,16676981234578, 58239643256916] |