n | a(n) |
---|---|
0 | 1 |
1 | 20 |
2 | 209 |
3 | 1520 |
4 | 8644 |
5 | 40944 |
6 | 168035 |
7 | 613756 |
8 | 2034120 |
9 | 6206596 |
10 | 17632836 |
11 | 47062620 |
12 | 118870650 |
13 | 285840940 |
14 | 657667521 |
15 | 1454009144 |
16 | 3100176535 |
17 | 6394814820 |
18 | 12796122680 |
19 | 24898749084 |
20 | 47210910669 |
21 | 87394933080 |
[1,20,209,1520,8644,40944,168035,613756,2034120, 6206596,17632836,47062620,118870650,285840940, 657667521,1454009144,3100176535,6394814820, 12796122680,24898749084,47210910669,87394933080] |