n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 4 |
4 | 9 |
5 | 21 |
6 | 51 |
7 | 128 |
8 | 327 |
9 | 858 |
10 | 2272 |
11 | 6146 |
12 | 16716 |
13 | 46246 |
14 | 128414 |
15 | 361493 |
16 | 1020506 |
17 | 2913060 |
18 | 8335405 |
19 | 24067930 |
20 | 69646035 |
[1,1,2,4,9,21,51,128,327,858,2272,6146,16716, 46246,128414,361493,1020506,2913060,8335405, 24067930,69646035] |