n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 84 |
5 | 555 |
6 | 4440 |
7 | 41265 |
8 | 438480 |
9 | 5240025 |
10 | 69582240 |
11 | 1016350335 |
12 | 16194911040 |
13 | 279560396115 |
14 | 5197054262400 |
15 | 103514720133825 |
16 | 2199255573715200 |
17 | 49645309340451825 |
18 | 1186599954328588800 |
19 | 29937224154635772975 |
20 | 795051251297099596800 |
[1,1,4,15,84,555,4440,41265,438480,5240025, 69582240,1016350335,16194911040,279560396115, 5197054262400,103514720133825,2199255573715200, 49645309340451825,1186599954328588800, 29937224154635772975,795051251297099596800] |