n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 12 |
4 | 44 |
5 | 175 |
6 | 762 |
7 | 3605 |
8 | 18384 |
9 | 100404 |
10 | 584070 |
11 | 3601895 |
12 | 23451540 |
13 | 160633681 |
14 | 1153896772 |
15 | 8668821600 |
16 | 67943174000 |
17 | 554327140739 |
18 | 4698491153454 |
19 | 41299244789989 |
20 | 375844030441560 |
[0,1,4,12,44,175,762,3605,18384,100404,584070, 3601895,23451540,160633681,1153896772,8668821600, 67943174000,554327140739,4698491153454, 41299244789989,375844030441560] |