A220233 - cp's OEIS frontend

A220233 Triangular array read by rows. T(n,k) is the number of labeled rooted trees of height at most 2 with exactly k leaves at a distance 1 from the root, n>=1, 0<=k<=n-1.

n	a(n)
1	0
2	0
3	2
4	6
5	0
6	3
7	12
8	24
9	0
10	4
11	80
12	60
13	60
14	0
15	5
16	390
17	480
18	180
19	120
20	0
21	6
22	2352
23	2730
24	1680
25	420
26	210
27	0
28	7
29	15176
30	18816
31	10920
32	4480
33	840
34	336
35	0
36	8
37	106416
38	136584
39	84672
40	32760
41	10080
42	1512
43	504
44	0
45	9
46	801450
47	1064160
48	682920
49	282240
50	81900
51	20160
52	2520
53	720
54	0
55	10

[0, 0, 2, 6, 0, 3, 12, 24, 0, 4, 80, 60, 60, 0, 5, 390, 480, 180, 120, 0, 6, 2352, 2730, 1680, 420, 210, 0, 7, 15176, 18816, 10920, 4480, 840, 336, 0, 8, 106416, 136584, 84672, 32760, 10080, 1512, 504, 0, 9, 801450, 1064160, 682920, 282240, 81900, 20160, 2520, 720, 0, 10]

cp's OEIS Frontend

A220233 Triangular array read by rows. T(n,k) is the number of labeled rooted trees of height at most 2 with exactly k leaves at a distance 1 from the root, n>=1, 0<=k<=n-1.

Table of values

List of values