n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 80 |
4 | 280 |
5 | 896 |
6 | 2688 |
7 | 7680 |
8 | 21120 |
9 | 56320 |
10 | 146432 |
11 | 372736 |
12 | 931840 |
13 | 2293760 |
14 | 5570560 |
15 | 13369344 |
16 | 31752192 |
17 | 74711040 |
18 | 174325760 |
19 | 403701760 |
20 | 928514048 |
21 | 2122317824 |
22 | 4823449600 |
23 | 10905190400 |
24 | 24536678400 |
25 | 54962159616 |
26 | 122607894528 |
[1,4,20,80,280,896,2688,7680,21120,56320,146432, 372736,931840,2293760,5570560,13369344,31752192, 74711040,174325760,403701760,928514048,2122317824, 4823449600,10905190400,24536678400,54962159616, 122607894528] |