n | a(n) |
---|---|
0 | 1 |
1 | 6 |
2 | 30 |
3 | 150 |
4 | 750 |
5 | 3735 |
6 | 18600 |
7 | 92640 |
8 | 461400 |
9 | 2298000 |
10 | 11445210 |
11 | 57003000 |
12 | 283904040 |
13 | 1413987000 |
14 | 7042377000 |
15 | 35074632060 |
16 | 174689570400 |
17 | 870043225440 |
18 | 4333259349600 |
19 | 21581843340000 |
20 | 107488595621160 |
21 | 535348070440800 |
[1,6,30,150,750,3735,18600,92640,461400,2298000, 11445210,57003000,283904040,1413987000,7042377000, 35074632060,174689570400,870043225440, 4333259349600,21581843340000,107488595621160, 535348070440800] |