A126220 - cp's OEIS frontend

A126220 Number of binary trees (i.e., rooted trees where each vertex has either 0, 1, or 2 children; and, when only one child is present, it is either a right child or a left child) with n edges and no adjacent vertices of outdegree 2.

n	a(n)
0	1
1	2
2	5
3	14
4	40
5	116
6	344
7	1040
8	3188
9	9880
10	30912
11	97520
12	309856
13	990656
14	3184672
15	10287808
16	33379072
17	108724864
18	355405568
19	1165521408
20	3833497408
21	12642775424
22	41799227392
23	138512751360
24	459973953024
25	1530498526208

[1, 2, 5, 14, 40, 116, 344, 1040, 3188, 9880, 30912, 97520, 309856, 990656, 3184672, 10287808, 33379072, 108724864, 355405568, 1165521408, 3833497408, 12642775424, 41799227392, 138512751360, 459973953024, 1530498526208]

cp's OEIS Frontend

A126220 Number of binary trees (i.e., rooted trees where each vertex has either 0, 1, or 2 children; and, when only one child is present, it is either a right child or a left child) with n edges and no adjacent vertices of outdegree 2.

Table of values

List of values