n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 3 |
5 | 17 |
6 | 131 |
7 | 915 |
8 | 6553 |
9 | 47026 |
10 | 341888 |
11 | 2505449 |
12 | 18534827 |
13 | 138224058 |
14 | 1038594326 |
15 | 7856087894 |
16 | 59782042225 |
17 | 457359506070 |
18 | 3515816578512 |
19 | 27143401299351 |
20 | 210372490707568 |
[0,0,0,3,17,131,915,6553,47026,341888,2505449, 18534827,138224058,1038594326,7856087894, 59782042225,457359506070,3515816578512, 27143401299351,210372490707568] |