A120988 - cp's OEIS frontend

A120988 Triangle read by rows: T(n,k) is the number of binary trees with n edges and such that the first leaf in the preorder traversal is at level k (1<=k<=n). A binary tree is a rooted tree in which each vertex has at most two children and each child of a vertex is designated as its left or right child.

n	a(n)
1	2
2	1
3	4
4	2
5	4
6	8
7	5
8	9
9	12
10	16
11	14
12	24
13	30
14	32
15	32
16	42
17	70
18	85
19	88
20	80
21	64
22	132
23	216
24	258
25	264
26	240
27	192
28	128
29	429
30	693
31	819
32	833
33	760
34	624
35	448
36	256
37	1430
38	2288
39	2684
40	2720
41	2490
42	2080
43	1568
44	1024
45	512
46	4862
47	7722
48	9009
49	9108
50	8361
51	7068
52	5488
53	3840
54	2304
55	1024

[2, 1, 4, 2, 4, 8, 5, 9, 12, 16, 14, 24, 30, 32, 32, 42, 70, 85, 88, 80, 64, 132, 216, 258, 264, 240, 192, 128, 429, 693, 819, 833, 760, 624, 448, 256, 1430, 2288, 2684, 2720, 2490, 2080, 1568, 1024, 512, 4862, 7722, 9009, 9108, 8361, 7068, 5488, 3840, 2304, 1024]

cp's OEIS Frontend

Table of values

List of values