n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 5 |
4 | 20 |
5 | 71 |
6 | 236 |
7 | 755 |
8 | 2360 |
9 | 7271 |
10 | 22196 |
11 | 67355 |
12 | 203600 |
13 | 613871 |
14 | 1847756 |
15 | 5555555 |
16 | 16691240 |
17 | 50122871 |
18 | 150466916 |
19 | 451597355 |
20 | 1355185280 |
21 | 4066342271 |
22 | 12200599676 |
23 | 36604944755 |
24 | 109821125720 |
25 | 329475960071 |
26 | 988453046036 |
27 | 2965409469755 |
28 | 8896329072560 |
[0,0,1,5,20,71,236,755,2360,7271,22196,67355, 203600,613871,1847756,5555555,16691240,50122871, 150466916,451597355,1355185280,4066342271, 12200599676,36604944755,109821125720,329475960071, 988453046036,2965409469755,8896329072560] |