n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 21 |
4 | 125 |
5 | 805 |
6 | 5459 |
7 | 38403 |
8 | 277667 |
9 | 2050771 |
10 | 15405655 |
11 | 117344350 |
12 | 904175038 |
13 | 7035182178 |
14 | 55197856415 |
15 | 436221495843 |
16 | 3469249248383 |
17 | 27744896161177 |
18 | 222987118478532 |
19 | 1800106801933350 |
20 | 14589674016207940 |
21 | 118674224290447850 |
22 | 968474133792224994 |
[1,1,4,21,125,805,5459,38403,277667,2050771, 15405655,117344350,904175038,7035182178, 55197856415,436221495843,3469249248383, 27744896161177,222987118478532,1800106801933350, 14589674016207940,118674224290447850, 968474133792224994] |