n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 4 |
3 | 0 |
4 | 52 |
5 | 194 |
6 | 808 |
7 | 2858 |
8 | 13998 |
9 | 66154 |
10 | 378268 |
11 | 1550370 |
12 | 7987672 |
13 | 37394810 |
14 | 190191026 |
15 | 958595712 |
16 | 4634180280 |
17 | 23153016922 |
18 | 114436235324 |
19 | 570764742248 |
20 | 2855728422214 |
21 | 14134719577328 |
22 | 70532689287114 |
23 | 350910293711340 |
24 | 1748728132235334 |
25 | 8722708834873854 |
[1,0,4,0,52,194,808,2858,13998,66154,378268, 1550370,7987672,37394810,190191026,958595712, 4634180280,23153016922,114436235324,570764742248, 2855728422214,14134719577328,70532689287114, 350910293711340,1748728132235334,8722708834873854] |