n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 18 |
3 | 64 |
4 | 215 |
5 | 660 |
6 | 1938 |
7 | 5400 |
8 | 14527 |
9 | 37728 |
10 | 95278 |
11 | 234344 |
12 | 563506 |
13 | 1326796 |
14 | 3066040 |
15 | 6963048 |
16 | 15564661 |
17 | 34282360 |
18 | 74486376 |
19 | 159785472 |
20 | 338703796 |
21 | 709957616 |
22 | 1472529670 |
23 | 3023894672 |
24 | 6151408852 |
25 | 12402137024 |
26 | 24792822174 |
27 | 49162962280 |
28 | 96737562642 |
[1,4,18,64,215,660,1938,5400,14527,37728,95278, 234344,563506,1326796,3066040,6963048,15564661, 34282360,74486376,159785472,338703796,709957616, 1472529670,3023894672,6151408852,12402137024, 24792822174,49162962280,96737562642] |