n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 4 |
4 | 15 |
5 | 252 |
6 | 924 |
7 | 11440 |
8 | 43758 |
9 | 497420 |
10 | 13123110 |
11 | 54627300 |
12 | 1251677700 |
13 | 12033222880 |
14 | 52860229080 |
15 | 511738760544 |
16 | 10363194502115 |
17 | 197548686920970 |
18 | 925029565741050 |
19 | 17302625882942400 |
20 | 161884603662657876 |
[1,1,4,15,252,924,11440,43758,497420,13123110, 54627300,1251677700,12033222880,52860229080, 511738760544,10363194502115,197548686920970, 925029565741050,17302625882942400, 161884603662657876] |