n | a(n) |
---|---|
2 | 0 |
3 | 1 |
4 | 4 |
5 | 13 |
6 | 44 |
7 | 149 |
8 | 498 |
9 | 1656 |
10 | 5498 |
11 | 18236 |
12 | 60456 |
13 | 200409 |
14 | 664464 |
15 | 2203755 |
16 | 7311894 |
17 | 24271290 |
18 | 80605250 |
19 | 267821525 |
20 | 890305418 |
21 | 2961015981 |
22 | 9852481830 |
23 | 32798011430 |
24 | 109229396466 |
25 | 363927233758 |
26 | 1213012655490 |
27 | 4044684629394 |
28 | 13491663770344 |
[0,1,4,13,44,149,498,1656,5498,18236,60456,200409, 664464,2203755,7311894,24271290,80605250, 267821525,890305418,2961015981,9852481830, 32798011430,109229396466,363927233758, 1213012655490,4044684629394,13491663770344] |