n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 4 |
4 | 10 |
5 | 15 |
6 | 49 |
7 | 147 |
8 | 407 |
9 | 1084 |
10 | 3010 |
11 | 8756 |
12 | 25145 |
13 | 73424 |
14 | 215375 |
15 | 631828 |
16 | 1870092 |
17 | 5562131 |
18 | 16584139 |
19 | 49630873 |
20 | 148917071 |
21 | 448088250 |
[0,0,4,10,15,49,147,407,1084,3010,8756,25145, 73424,215375,631828,1870092,5562131,16584139, 49630873,148917071,448088250] |