n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 4 |
3 | 18 |
4 | 48 |
5 | 150 |
6 | 324 |
7 | 882 |
8 | 1920 |
9 | 4536 |
10 | 9900 |
11 | 22506 |
12 | 48240 |
13 | 106470 |
14 | 227556 |
15 | 490950 |
16 | 1044480 |
17 | 2228190 |
18 | 4708368 |
19 | 9961434 |
20 | 20950800 |
21 | 44037378 |
22 | 92229588 |
23 | 192937938 |
24 | 402549120 |
25 | 838860000 |
26 | 1744617420 |
27 | 3623864832 |
28 | 7515733680 |
[1,2,4,18,48,150,324,882,1920,4536,9900,22506, 48240,106470,227556,490950,1044480,2228190, 4708368,9961434,20950800,44037378,92229588, 192937938,402549120,838860000,1744617420, 3623864832,7515733680] |