n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 2 |
4 | 4 |
5 | 9 |
6 | 20 |
7 | 51 |
8 | 121 |
9 | 321 |
10 | 826 |
11 | 2186 |
12 | 5789 |
13 | 16114 |
14 | 42449 |
15 | 118281 |
16 | 328425 |
17 | 908933 |
18 | 2510553 |
19 | 7138324 |
20 | 19869748 |
[1,1,2,4,9,20,51,121,321,826,2186,5789,16114, 42449,118281,328425,908933,2510553,7138324, 19869748] |