n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 0 |
3 | 0 |
4 | 1 |
5 | 4 |
6 | 13 |
7 | 39 |
8 | 117 |
9 | 351 |
10 | 1054 |
11 | 3163 |
12 | 9490 |
13 | 28470 |
14 | 85410 |
15 | 256230 |
16 | 768691 |
17 | 2306074 |
18 | 6918223 |
19 | 20754669 |
20 | 62264007 |
21 | 186792021 |
22 | 560376064 |
23 | 1681128193 |
24 | 5043384580 |
25 | 15130153740 |
26 | 45390461220 |
27 | 136171383660 |
[0,0,0,0,1,4,13,39,117,351,1054,3163,9490,28470, 85410,256230,768691,2306074,6918223,20754669, 62264007,186792021,560376064,1681128193, 5043384580,15130153740,45390461220,136171383660] |