n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 18 |
4 | 72 |
5 | 320 |
6 | 1414 |
7 | 6346 |
8 | 28766 |
9 | 131246 |
10 | 602390 |
11 | 2777638 |
12 | 12857572 |
13 | 59712940 |
14 | 278096674 |
15 | 1298309782 |
16 | 6074112952 |
17 | 28470828008 |
18 | 133671581490 |
19 | 628526085270 |
20 | 2959291856816 |
21 | 13950087683416 |
22 | 65832860408434 |
23 | 310987879638926 |
[1,4,18,72,320,1414,6346,28766,131246,602390, 2777638,12857572,59712940,278096674,1298309782, 6074112952,28470828008,133671581490,628526085270, 2959291856816,13950087683416,65832860408434, 310987879638926] |