n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 3 |
3 | 12 |
4 | 64 |
5 | 420 |
6 | 3246 |
7 | 28798 |
8 | 288072 |
9 | 3205044 |
10 | 39234340 |
11 | 523821936 |
12 | 7572221328 |
13 | 117792884872 |
14 | 1961516974704 |
15 | 34807390821960 |
16 | 655594811020096 |
17 | 13060711726818768 |
18 | 274358217793164912 |
19 | 6060159633360214144 |
20 | 140404595387426964480 |
[0,1,3,12,64,420,3246,28798,288072,3205044, 39234340,523821936,7572221328,117792884872, 1961516974704,34807390821960,655594811020096, 13060711726818768,274358217793164912, 6060159633360214144,140404595387426964480] |