n | a(n) |
---|---|
2 | 1 |
3 | 2 |
4 | 21 |
5 | 204 |
6 | 2605 |
7 | 39990 |
8 | 720601 |
9 | 14913080 |
10 | 348678441 |
11 | 9090909090 |
12 | 261535698061 |
13 | 8230246567620 |
14 | 281241170407093 |
15 | 10371206370520814 |
16 | 410525522232055665 |
17 | 17361641481138401520 |
18 | 781282469559318055057 |
19 | 37275544492386193492506 |
20 | 1879498672877297909667781 |
[1,2,21,204,2605,39990,720601,14913080,348678441, 9090909090,261535698061,8230246567620, 281241170407093,10371206370520814, 410525522232055665,17361641481138401520, 781282469559318055057,37275544492386193492506, 1879498672877297909667781] |