n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 12 |
4 | 40 |
5 | 120 |
6 | 396 |
7 | 1260 |
8 | 4176 |
9 | 13788 |
10 | 46240 |
11 | 155496 |
12 | 527160 |
13 | 1792804 |
14 | 6125028 |
15 | 20986020 |
16 | 72117632 |
17 | 248396792 |
18 | 857402748 |
19 | 2964896876 |
20 | 10269550040 |
21 | 35622420288 |
22 | 123727866768 |
23 | 430254861944 |
24 | 1497796242288 |
25 | 5219231003500 |
[1,4,12,40,120,396,1260,4176,13788,46240,155496, 527160,1792804,6125028,20986020,72117632, 248396792,857402748,2964896876,10269550040, 35622420288,123727866768,430254861944, 1497796242288,5219231003500] |