n | a(n) |
---|---|
2 | 1 |
3 | 4 |
4 | 13 |
5 | 40 |
6 | 120 |
7 | 352 |
8 | 1022 |
9 | 2948 |
10 | 8473 |
11 | 24304 |
12 | 69649 |
13 | 199544 |
14 | 571795 |
15 | 1639244 |
16 | 4702499 |
17 | 13500396 |
18 | 38790727 |
19 | 111555296 |
20 | 321100627 |
21 | 925086012 |
22 | 2667533646 |
23 | 7698716068 |
24 | 22238169212 |
25 | 64289860528 |
26 | 186010834243 |
27 | 538611262492 |
[1,4,13,40,120,352,1022,2948,8473,24304,69649, 199544,571795,1639244,4702499,13500396,38790727, 111555296,321100627,925086012,2667533646, 7698716068,22238169212,64289860528,186010834243, 538611262492] |