n | a(n) |
---|---|
1 | 0 |
2 | 4 |
3 | 12 |
4 | 48 |
5 | 144 |
6 | 468 |
7 | 1404 |
8 | 4320 |
9 | 12960 |
10 | 39204 |
11 | 117612 |
12 | 353808 |
13 | 1061424 |
14 | 3187188 |
15 | 9561564 |
16 | 28693440 |
17 | 86080320 |
18 | 258267204 |
19 | 774801612 |
20 | 2324483568 |
21 | 6973450704 |
22 | 20920588308 |
23 | 62761764924 |
24 | 188286003360 |
25 | 564858010080 |
26 | 1694576156004 |
[0,4,12,48,144,468,1404,4320,12960,39204,117612, 353808,1061424,3187188,9561564,28693440,86080320, 258267204,774801612,2324483568,6973450704, 20920588308,62761764924,188286003360,564858010080, 1694576156004] |