n | a(n) |
---|---|
0 | 0 |
1 | 0 |
2 | 1 |
3 | 4 |
4 | 12 |
5 | 36 |
6 | 109 |
7 | 328 |
8 | 984 |
9 | 2952 |
10 | 8857 |
11 | 26572 |
12 | 79716 |
13 | 239148 |
14 | 717445 |
15 | 2152336 |
16 | 6457008 |
17 | 19371024 |
18 | 58113073 |
19 | 174339220 |
20 | 523017660 |
21 | 1569052980 |
22 | 4707158941 |
23 | 14121476824 |
24 | 42364430472 |
25 | 127093291416 |
[0,0,1,4,12,36,109,328,984,2952,8857,26572,79716, 239148,717445,2152336,6457008,19371024,58113073, 174339220,523017660,1569052980,4707158941, 14121476824,42364430472,127093291416] |