n | a(n) |
---|---|
1 | 3 |
2 | 15 |
3 | 42 |
4 | 186 |
5 | 399 |
6 | 1680 |
7 | 3282 |
8 | 15876 |
9 | 31836 |
10 | 123690 |
11 | 277344 |
12 | 1541568 |
13 | 2391486 |
14 | 8992680 |
15 | 25483332 |
16 | 111757968 |
17 | 193819392 |
18 | 967814400 |
19 | 1744488660 |
20 | 9366647892 |
21 | 16912999320 |
22 | 62424587520 |
23 | 144219337920 |
24 | 852903426816 |
25 | 1397135488896 |
26 | 4766016364260 |
27 | 12477973754400 |
[3,15,42,186,399,1680,3282,15876,31836,123690, 277344,1541568,2391486,8992680,25483332,111757968, 193819392,967814400,1744488660,9366647892, 16912999320,62424587520,144219337920,852903426816, 1397135488896,4766016364260,12477973754400] |