n | a(n) |
---|---|
1 | 1 |
2 | 2 |
3 | 4 |
4 | 9 |
5 | 20 |
6 | 64 |
7 | 216 |
8 | 906 |
9 | 4178 |
10 | 21222 |
11 | 116064 |
12 | 678790 |
13 | 4213830 |
14 | 27645030 |
15 | 190899972 |
16 | 1382960445 |
17 | 10480143744 |
18 | 82864876682 |
19 | 682076810340 |
20 | 5832742233094 |
21 | 51724158246750 |
22 | 474869816290526 |
23 | 4506715738475980 |
[1,2,4,9,20,64,216,906,4178,21222,116064,678790, 4213830,27645030,190899972,1382960445,10480143744, 82864876682,682076810340,5832742233094, 51724158246750,474869816290526,4506715738475980] |