n | a(n) |
---|---|
1 | 0 |
2 | 2 |
3 | 12 |
4 | 70 |
5 | 426 |
6 | 2708 |
7 | 17846 |
8 | 121014 |
9 | 839388 |
10 | 5929162 |
11 | 42509318 |
12 | 308561388 |
13 | 2263197114 |
14 | 16748071210 |
15 | 124893822012 |
16 | 937612685502 |
17 | 7080464093282 |
18 | 53748285892004 |
19 | 409909445733950 |
20 | 3139241855256334 |
21 | 24132284421690988 |
[0,2,12,70,426,2708,17846,121014,839388,5929162, 42509318,308561388,2263197114,16748071210, 124893822012,937612685502,7080464093282, 53748285892004,409909445733950,3139241855256334, 24132284421690988] |