n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 1 |
4 | 2 |
5 | 9 |
6 | 36 |
7 | 154 |
8 | 684 |
9 | 3128 |
10 | 14666 |
11 | 70258 |
12 | 342766 |
13 | 1698625 |
14 | 8532410 |
15 | 43368153 |
16 | 222729492 |
17 | 1154455161 |
18 | 6033034032 |
19 | 31760434883 |
20 | 168311948410 |
21 | 897327111964 |
22 | 4810159375532 |
23 | 25914118276362 |
[1,0,1,2,9,36,154,684,3128,14666,70258,342766, 1698625,8532410,43368153,222729492,1154455161, 6033034032,31760434883,168311948410,897327111964, 4810159375532,25914118276362] |