n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 2 |
3 | 12 |
4 | 60 |
5 | 340 |
6 | 2310 |
7 | 18354 |
8 | 165592 |
9 | 1664424 |
10 | 18410130 |
11 | 222085270 |
12 | 2901011124 |
13 | 40790592492 |
14 | 614247917374 |
15 | 9862468172970 |
16 | 168192316357680 |
17 | 3036117383306704 |
18 | 57835808554908042 |
19 | 1159445925005561694 |
20 | 24400842327684259660 |
21 | 537878773763482265940 |
[0,0,2,12,60,340,2310,18354,165592,1664424, 18410130,222085270,2901011124,40790592492, 614247917374,9862468172970,168192316357680, 3036117383306704,57835808554908042, 1159445925005561694,24400842327684259660, 537878773763482265940] |