n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 4 |
4 | 12 |
5 | 57 |
6 | 321 |
7 | 2176 |
8 | 17008 |
9 | 150505 |
10 | 1485465 |
11 | 16170036 |
12 | 192384876 |
13 | 2483177809 |
14 | 34554278857 |
15 | 515620794592 |
16 | 8212685046336 |
17 | 139062777326001 |
18 | 2494364438359953 |
19 | 47245095998005060 |
20 | 942259727190907180 |
21 | 19737566982241851721 |
22 | 433234326593362631601 |
[1,1,4,12,57,321,2176,17008,150505,1485465, 16170036,192384876,2483177809,34554278857, 515620794592,8212685046336,139062777326001, 2494364438359953,47245095998005060, 942259727190907180,19737566982241851721, 433234326593362631601] |