n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 11 |
4 | 30 |
5 | 85 |
6 | 244 |
7 | 715 |
8 | 2118 |
9 | 6309 |
10 | 18860 |
11 | 56475 |
12 | 169262 |
13 | 507541 |
14 | 1522244 |
15 | 4566155 |
16 | 13697590 |
17 | 41091429 |
18 | 123272252 |
19 | 369813659 |
20 | 1109436254 |
[0,1,4,11,30,85,244,715,2118,6309,18860,56475, 169262,507541,1522244,4566155,13697590,41091429, 123272252,369813659,1109436254] |