n | a(n) |
---|---|
0 | 1 |
1 | 21 |
2 | 135 |
3 | 693 |
4 | 4159 |
5 | 25291 |
6 | 157635 |
7 | 995659 |
8 | 6357119 |
9 | 40921479 |
10 | 265145505 |
11 | 1727138841 |
12 | 11300204035 |
13 | 74208972755 |
14 | 488874737353 |
15 | 3229363648333 |
16 | 21382430152111 |
17 | 141869013922279 |
18 | 942972599847861 |
19 | 6277675948529895 |
[1,21,135,693,4159,25291,157635,995659,6357119, 40921479,265145505,1727138841,11300204035, 74208972755,488874737353,3229363648333, 21382430152111,141869013922279,942972599847861, 6277675948529895] |