n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 1 |
4 | 2 |
5 | 6 |
6 | 18 |
7 | 78 |
8 | 312 |
9 | 2070 |
10 | 12420 |
11 | 163878 |
12 | 1966536 |
13 | 62213526 |
14 | 1866405780 |
15 | 206591803854 |
16 | 22311914816232 |
17 | 9436063264020024 |
18 | 3963146570888410080 |
19 | 9887814229774042889370 |
20 | 24620657432137366794531300 |
[1,1,1,2,6,18,78,312,2070,12420,163878,1966536, 62213526,1866405780,206591803854,22311914816232, 9436063264020024,3963146570888410080, 9887814229774042889370,24620657432137366794531300] |