n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 6 |
3 | 18 |
4 | 54 |
5 | 174 |
6 | 582 |
7 | 1974 |
8 | 6726 |
9 | 22950 |
10 | 78342 |
11 | 267462 |
12 | 913158 |
13 | 3117702 |
14 | 10644486 |
15 | 36342534 |
16 | 124081158 |
17 | 423639558 |
18 | 1446395910 |
19 | 4938304518 |
20 | 16860426246 |
21 | 57565095942 |
22 | 196539531270 |
23 | 671027933190 |
24 | 2291032670214 |
25 | 7822074814470 |
26 | 26706233917446 |
27 | 91180786040838 |
[0,0,6,18,54,174,582,1974,6726,22950,78342,267462, 913158,3117702,10644486,36342534,124081158, 423639558,1446395910,4938304518,16860426246, 57565095942,196539531270,671027933190, 2291032670214,7822074814470,26706233917446, 91180786040838] |