n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 2 |
4 | 7 |
5 | 20 |
6 | 61 |
7 | 182 |
8 | 546 |
9 | 1632 |
10 | 4875 |
11 | 14542 |
12 | 43340 |
13 | 129064 |
14 | 384111 |
15 | 1142610 |
16 | 3397656 |
17 | 10100448 |
18 | 30020283 |
19 | 89213094 |
20 | 265096455 |
21 | 787695636 |
22 | 2340488535 |
23 | 6954401762 |
24 | 20664628438 |
25 | 61406952800 |
26 | 182488572045 |
27 | 542358944946 |
[0,0,1,2,7,20,61,182,546,1632,4875,14542,43340, 129064,384111,1142610,3397656,10100448,30020283, 89213094,265096455,787695636,2340488535, 6954401762,20664628438,61406952800,182488572045, 542358944946] |