n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 15 |
3 | 56 |
4 | 207 |
5 | 764 |
6 | 2805 |
7 | 10288 |
8 | 37609 |
9 | 137380 |
10 | 500655 |
11 | 1823440 |
12 | 6629423 |
13 | 24090332 |
14 | 87418221 |
15 | 317085352 |
16 | 1148825185 |
17 | 4160744164 |
18 | 15054719697 |
19 | 54454345624 |
20 | 196805925995 |
21 | 711077858188 |
22 | 2567375653681 |
23 | 9267176552040 |
[1,4,15,56,207,764,2805,10288,37609,137380,500655, 1823440,6629423,24090332,87418221,317085352, 1148825185,4160744164,15054719697,54454345624, 196805925995,711077858188,2567375653681, 9267176552040] |