n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 14 |
3 | 45 |
4 | 139 |
5 | 422 |
6 | 1272 |
7 | 3823 |
8 | 11477 |
9 | 34440 |
10 | 103330 |
11 | 310001 |
12 | 930015 |
13 | 2790058 |
14 | 8370188 |
15 | 25110579 |
16 | 75331753 |
17 | 225995276 |
18 | 677985846 |
19 | 2033957557 |
20 | 6101872691 |
21 | 18305618094 |
22 | 54916854304 |
23 | 164750562935 |
24 | 494251688829 |
25 | 1482755066512 |
[1,4,14,45,139,422,1272,3823,11477,34440,103330, 310001,930015,2790058,8370188,25110579,75331753, 225995276,677985846,2033957557,6101872691, 18305618094,54916854304,164750562935,494251688829, 1482755066512] |