n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 104 |
4 | 548 |
5 | 2904 |
6 | 15432 |
7 | 82128 |
8 | 437444 |
9 | 2331128 |
10 | 12426200 |
11 | 66250672 |
12 | 353258536 |
13 | 1883768176 |
14 | 10045773072 |
15 | 53573890464 |
16 | 285714489348 |
17 | 1523763466296 |
18 | 8126565627192 |
19 | 43341046493424 |
20 | 231149891614008 |
21 | 1232790669780816 |
22 | 6574850950474992 |
23 | 35065749759115104 |
[1,4,20,104,548,2904,15432,82128,437444,2331128, 12426200,66250672,353258536,1883768176, 10045773072,53573890464,285714489348, 1523763466296,8126565627192,43341046493424, 231149891614008,1232790669780816,6574850950474992, 35065749759115104] |