n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 2 |
3 | 2 |
4 | 8 |
5 | 20 |
6 | 60 |
7 | 212 |
8 | 632 |
9 | 2508 |
10 | 8280 |
11 | 34256 |
12 | 127712 |
13 | 542984 |
14 | 2252432 |
15 | 9873216 |
16 | 44557424 |
17 | 202661012 |
18 | 975470880 |
19 | 4627469192 |
20 | 23413518704 |
21 | 116147688600 |
22 | 611882489152 |
23 | 3174544514192 |
24 | 17312022302368 |
25 | 93772475206800 |
26 | 527582381206400 |
27 | 2975078868145952 |
[0,0,2,2,8,20,60,212,632,2508,8280,34256,127712, 542984,2252432,9873216,44557424,202661012, 975470880,4627469192,23413518704,116147688600, 611882489152,3174544514192,17312022302368, 93772475206800,527582381206400,2975078868145952] |