n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 9 |
3 | 30 |
4 | 110 |
5 | 442 |
6 | 1908 |
7 | 8822 |
8 | 43330 |
9 | 224595 |
10 | 1221860 |
11 | 6953514 |
12 | 41232563 |
13 | 253992215 |
14 | 1620599471 |
15 | 10689986451 |
16 | 72734177909 |
17 | 509288018981 |
18 | 3663185604591 |
19 | 27027424720210 |
20 | 204246277508032 |
21 | 1578970198567932 |
[1,3,9,30,110,442,1908,8822,43330,224595,1221860, 6953514,41232563,253992215,1620599471,10689986451, 72734177909,509288018981,3663185604591, 27027424720210,204246277508032,1578970198567932] |