n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 1 |
4 | 3 |
5 | 12 |
6 | 38 |
7 | 117 |
8 | 336 |
9 | 976 |
10 | 2724 |
11 | 7689 |
12 | 21455 |
13 | 60228 |
14 | 168714 |
15 | 475037 |
16 | 1338861 |
17 | 3788400 |
18 | 10742588 |
19 | 30556305 |
20 | 87112059 |
21 | 248967564 |
22 | 713032782 |
23 | 2046325125 |
24 | 5883428618 |
25 | 16944975048 |
26 | 48880471500 |
27 | 141212377489 |
28 | 408509453511 |
29 | 1183275193908 |
30 | 3431504760514 |
[0,0,0,1,3,12,38,117,336,976,2724,7689,21455, 60228,168714,475037,1338861,3788400,10742588, 30556305,87112059,248967564,713032782,2046325125, 5883428618,16944975048,48880471500,141212377489, 408509453511,1183275193908,3431504760514] |