A131889 - cp's OEIS frontend

A131889 a(n) is the number of shapes of balanced trees with constant branching factor 3 and n nodes. The node is balanced if the size, measured in nodes, of each pair of its children differ by at most one node.

n	a(n)
0	1
1	1
2	3
3	3
4	1
5	9
6	27
7	27
8	81
9	81
10	27
11	27
12	9
13	1
14	27
15	243
16	729
17	6561
18	19683
19	19683
20	59049
21	59049
22	19683
23	177147
24	531441
25	531441
26	1594323
27	1594323
28	531441
29	531441
30	177147
31	19683
32	59049
33	59049
34	19683
35	19683
36	6561
37	729
38	243
39	27
40	1
41	81
42	2187
43	19683
44	531441
45	4782969

[1, 1, 3, 3, 1, 9, 27, 27, 81, 81, 27, 27, 9, 1, 27, 243, 729, 6561, 19683, 19683, 59049, 59049, 19683, 177147, 531441, 531441, 1594323, 1594323, 531441, 531441, 177147, 19683, 59049, 59049, 19683, 19683, 6561, 729, 243, 27, 1, 81, 2187, 19683, 531441, 4782969]

cp's OEIS Frontend

A131889 a(n) is the number of shapes of balanced trees with constant branching factor 3 and n nodes. The node is balanced if the size, measured in nodes, of each pair of its children differ by at most one node.

Table of values

List of values