n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 3 |
3 | 9 |
4 | 27 |
5 | 81 |
6 | 240 |
7 | 711 |
8 | 2094 |
9 | 6152 |
10 | 18012 |
11 | 52613 |
12 | 153297 |
13 | 445772 |
14 | 1293780 |
15 | 3748820 |
16 | 10845935 |
17 | 31336532 |
18 | 90426198 |
19 | 260644262 |
20 | 750502831 |
21 | 2158961013 |
22 | 6205225334 |
23 | 17820505454 |
24 | 51139664497 |
25 | 146654181925 |
26 | 420291420558 |
[0,1,3,9,27,81,240,711,2094,6152,18012,52613, 153297,445772,1293780,3748820,10845935,31336532, 90426198,260644262,750502831,2158961013, 6205225334,17820505454,51139664497,146654181925, 420291420558] |