n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 15 |
4 | 50 |
5 | 161 |
6 | 504 |
7 | 1554 |
8 | 4740 |
9 | 14355 |
10 | 43252 |
11 | 129844 |
12 | 388752 |
13 | 1161615 |
14 | 3465840 |
15 | 10329336 |
16 | 30759120 |
17 | 91538523 |
18 | 272290140 |
19 | 809676735 |
20 | 2407049106 |
21 | 7154586747 |
22 | 21263575256 |
23 | 63191778950 |
24 | 187790510700 |
25 | 558069593445 |
26 | 1658498131836 |
[1,4,15,50,161,504,1554,4740,14355,43252,129844, 388752,1161615,3465840,10329336,30759120,91538523, 272290140,809676735,2407049106,7154586747, 21263575256,63191778950,187790510700,558069593445, 1658498131836] |