n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 1 |
3 | 1 |
4 | 4 |
5 | 9 |
6 | 27 |
7 | 78 |
8 | 231 |
9 | 715 |
10 | 2193 |
11 | 6954 |
12 | 21999 |
13 | 70840 |
14 | 228896 |
15 | 746650 |
16 | 2447757 |
17 | 8072208 |
18 | 26745627 |
19 | 89002364 |
20 | 297344960 |
21 | 996865397 |
22 | 3352918429 |
23 | 11310307593 |
24 | 38256171642 |
25 | 129718262583 |
26 | 440855654827 |
27 | 1501451066767 |
28 | 5123671576890 |
29 | 17516503865294 |
[1,0,1,1,4,9,27,78,231,715,2193,6954,21999,70840, 228896,746650,2447757,8072208,26745627,89002364, 297344960,996865397,3352918429,11310307593, 38256171642,129718262583,440855654827, 1501451066767,5123671576890,17516503865294] |