n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 12 |
5 | 42 |
6 | 180 |
7 | 561 |
8 | 1833 |
9 | 5373 |
10 | 15798 |
11 | 44367 |
12 | 123561 |
13 | 336243 |
14 | 906054 |
15 | 2408094 |
16 | 6344832 |
17 | 16561824 |
18 | 42922602 |
19 | 110472933 |
20 | 282678423 |
21 | 719404803 |
22 | 1822117962 |
23 | 4594816221 |
24 | 11540742615 |
25 | 28880919975 |
26 | 72033463644 |
27 | 179107709004 |
[0,0,0,0,12,42,180,561,1833,5373,15798,44367, 123561,336243,906054,2408094,6344832,16561824, 42922602,110472933,282678423,719404803,1822117962, 4594816221,11540742615,28880919975,72033463644, 179107709004] |