n | a(n) |
---|---|
0 | 1 |
1 | 21 |
2 | 252 |
3 | 2268 |
4 | 17010 |
5 | 112266 |
6 | 673596 |
7 | 3752892 |
8 | 19702683 |
9 | 98513415 |
10 | 472864392 |
11 | 2192371272 |
12 | 9865670724 |
13 | 43257171636 |
14 | 185387878440 |
15 | 778629089448 |
16 | 3211844993973 |
17 | 13036312034361 |
18 | 52145248137444 |
19 | 205836505805700 |
20 | 802762372642230 |
21 | 3096369151620030 |
[1,21,252,2268,17010,112266,673596,3752892, 19702683,98513415,472864392,2192371272,9865670724, 43257171636,185387878440,778629089448, 3211844993973,13036312034361,52145248137444, 205836505805700,802762372642230,3096369151620030] |