A139263 - cp's OEIS frontend

A139263 Number of two element anti-chains in Riordan trees on n edges (also called non-redundant trees, i.e., ordered trees where no vertex has out-degree equal to 1).

n	a(n)
0	0
1	0
2	1
3	3
4	14
5	48
6	172
7	580
8	1941
9	6373
10	20725
11	66763
12	213575
13	679141
14	2148948
15	6771068
16	21257741
17	66529077
18	207639925
19	646480555
20	2008458669
21	6227766899
22	19277394308
23	59577651108
24	183865477474
25	566700165898
26	1744578701517
27	5364804428455
28	16480883532586
29	50582859417868
30	155114365434224

[0, 0, 1, 3, 14, 48, 172, 580, 1941, 6373, 20725, 66763, 213575, 679141, 2148948, 6771068, 21257741, 66529077, 207639925, 646480555, 2008458669, 6227766899, 19277394308, 59577651108, 183865477474, 566700165898, 1744578701517, 5364804428455, 16480883532586, 50582859417868, 155114365434224]

cp's OEIS Frontend

A139263 Number of two element anti-chains in Riordan trees on n edges (also called non-redundant trees, i.e., ordered trees where no vertex has out-degree equal to 1).

Table of values

List of values