n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 4 |
3 | 12 |
4 | 44 |
5 | 220 |
6 | 1228 |
7 | 7196 |
8 | 45004 |
9 | 303900 |
10 | 2201676 |
11 | 16920860 |
12 | 136966860 |
13 | 1163989788 |
14 | 10364408140 |
15 | 96463232284 |
16 | 935872773068 |
17 | 9440653262620 |
18 | 98809201693260 |
19 | 1071131795708188 |
20 | 12007932126074060 |
[1,0,4,12,44,220,1228,7196,45004,303900,2201676, 16920860,136966860,1163989788,10364408140, 96463232284,935872773068,9440653262620, 98809201693260,1071131795708188,12007932126074060] |