n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 5 |
4 | 15 |
5 | 52 |
6 | 203 |
7 | 877 |
8 | 4139 |
9 | 21119 |
10 | 115495 |
11 | 671969 |
12 | 4132936 |
13 | 26723063 |
14 | 180775027 |
15 | 1274056792 |
16 | 9320514343 |
17 | 70548979894 |
18 | 550945607475 |
19 | 4427978077331 |
20 | 36544023687590 |
[1,1,2,5,15,52,203,877,4139,21119,115495,671969, 4132936,26723063,180775027,1274056792,9320514343, 70548979894,550945607475,4427978077331, 36544023687590] |