n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 28 |
3 | 221 |
4 | 1834 |
5 | 15657 |
6 | 136137 |
7 | 1199014 |
8 | 10661184 |
9 | 95493145 |
10 | 860339723 |
11 | 7788028028 |
12 | 70777321331 |
13 | 645359630071 |
14 | 5901209474518 |
15 | 54093485799726 |
16 | 496910913391428 |
17 | 4573312196055502 |
18 | 42160889572810597 |
19 | 389258294230352460 |
20 | 3598732127428879981 |
[1,4,28,221,1834,15657,136137,1199014,10661184, 95493145,860339723,7788028028,70777321331, 645359630071,5901209474518,54093485799726, 496910913391428,4573312196055502, 42160889572810597,389258294230352460, 3598732127428879981] |