n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 6 |
4 | 21 |
5 | 112 |
6 | 717 |
7 | 4592 |
8 | 38857 |
9 | 318208 |
10 | 3158329 |
11 | 32169984 |
12 | 363525789 |
13 | 4399544320 |
14 | 56250039237 |
15 | 779244812288 |
16 | 11210469917713 |
17 | 173483433263104 |
18 | 2783865475754737 |
19 | 47421793222656000 |
20 | 840008000833503141 |
[1,1,1,6,21,112,717,4592,38857,318208,3158329, 32169984,363525789,4399544320,56250039237, 779244812288,11210469917713,173483433263104, 2783865475754737,47421793222656000, 840008000833503141] |