n | a(n) |
---|---|
1 | 2 |
2 | 6 |
3 | 31 |
4 | 180 |
5 | 1101 |
6 | 6901 |
7 | 43828 |
8 | 280664 |
9 | 1807909 |
10 | 11698479 |
11 | 75973701 |
12 | 494890116 |
13 | 3231949644 |
14 | 21153128028 |
15 | 138712184488 |
[2,6,31,180,1101,6901,43828,280664,1807909, 11698479,75973701,494890116,3231949644, 21153128028,138712184488] |